Treaty of Westphalia 1648

Introduction

The Treaty of Westphalia is frequently cited as a foundational reference point in the development of public international law, particularly in discussions concerning territorial sovereignty, state autonomy, and the structure of the international system. Concluded in 1648 through two interconnected peace agreements negotiated in Münster and Osnabrück, the Westphalian settlement brought an end to the Thirty Years’ War and addressed a deep systemic crisis in European political and legal order. Its enduring relevance lies not in symbolic claims about the “birth” of modern international law, but in the concrete legal arrangements it stabilised and the patterns of interstate conduct it reinforced.

Before 1648, Europe was governed by a fragmented and overlapping system of authority. Political power was dispersed among emperors, kings, princes, and ecclesiastical institutions, with no clear hierarchy capable of imposing lasting legal order. The Holy Roman Empire operated as a complex constitutional structure rather than a unified sovereign entity, while religious allegiance continued to generate external intervention and internal conflict. The Thirty Years’ War exposed the structural weaknesses of this arrangement, combining religious disputes, dynastic competition, and foreign involvement into a prolonged conflict that devastated large parts of Central Europe and demonstrated the absence of effective legal constraints on the use of force (Wilson, 2009).

The Westphalian peace settlement was negotiated as a pragmatic response to this breakdown. It was shaped by diplomatic necessity rather than legal theory, yet it produced outcomes of lasting juridical significance. The treaties confirmed the authority of rulers and political entities within defined territories, formalised limits on external interference in domestic religious and political affairs, and recognised the coexistence of multiple autonomous actors within a shared legal framework. These provisions did not abolish hierarchy or power politics, but they reoriented the European order toward territorial governance and mutual legal recognition as the basis for stability (Osiander, 2001).

Claims that the settlement created modern sovereignty or the contemporary state system tend to oversimplify its effects. Concepts associated with sovereignty existed well before the mid-seventeenth century, and dynastic rule remained dominant for centuries after. The significance of the Westphalian agreements lies instead in their consolidating function. They transformed existing practices into mutually accepted legal commitments and embedded them in treaty form, thereby strengthening the normative expectation that political authority would be exercised within territorial limits and respected by external actors (Croxton, 1999).

This article approaches the subject as a legal settlement grounded in historical context rather than as an abstract theoretical milestone. By examining the treaties’ structure, purposes, and practical consequences, the analysis seeks to clarify what the Westphalian agreements actually regulated, how they reshaped relations among political entities, and why their legacy continues to inform contemporary debates on sovereignty and international order. All references and sources are cited in Harvard style and will be consolidated in a dedicated references section at the end of the article.

1. Historical Context: Europe Before Westphalia

1.1 Political and legal order in pre-1648 Europe

Early modern Europe was characterised by a highly fragmented legal and political structure in which authority was neither centralised nor territorially exclusive. The Holy Roman Empire exemplified this condition. Rather than functioning as a sovereign state, it operated as a composite constitutional order composed of emperors, electors, princes, free cities, and ecclesiastical authorities, each exercising varying degrees of autonomy. Imperial authority existed, but it was constrained by customary privileges, feudal obligations, and negotiated limits on central power (Whaley, 2012).

Jurisdictional authority overlapped extensively. Secular rulers exercised governance over lands and populations, yet their power often coexisted with, or was challenged by, ecclesiastical institutions claiming independent authority grounded in canon law. Bishops and abbots governed territories as temporal lords, while the papacy asserted a broader normative influence over Christian rulers. This coexistence of secular and religious legal orders produced persistent uncertainty over who possessed final authority in matters of governance, justice, and allegiance (Berman, 1983).

A defining feature of this period was the absence of a coherent doctrine of territorial sovereignty. Political authority was personal, dynastic, and relational rather than territorial in the modern legal sense. Rulers governed by virtue of titles, feudal bonds, and religious legitimacy, not by exclusive jurisdiction over a clearly demarcated space. As a result, intervention across political boundaries was common and often justified by religious solidarity, dynastic claims, or imperial prerogatives. No generally accepted legal principle limited such interference, nor was there a stable framework regulating relations among political entities as formally equal actors (Skinner, 1978).

1.2 The Thirty Years’ War (1618–1648)

The Thirty Years’ War emerged from this unstable order and exposed its structural weaknesses. The conflict originated in religious tensions within the Holy Roman Empire, particularly between Catholic authorities and Protestant estates, but quickly expanded into a broader struggle involving dynastic ambition, imperial authority, and external intervention by major European powers. Religious divisions provided the initial catalyst, yet political calculations soon dominated the conduct and expansion of the war (Wilson, 2009).

Dynastic rivalry played a decisive role as France, Sweden, Spain, and other powers intervened to advance strategic interests, often irrespective of confessional alignment. The emperor’s attempts to reassert central authority over the imperial estates intensified resistance and prolonged hostilities. The war thus became a multilayered conflict in which religious identity, territorial control, and balance-of-power considerations were deeply intertwined (Parker, 1997).

The scale of destruction was unprecedented. Large areas of Central Europe suffered severe population loss, economic collapse, and social disintegration. Entire regions were depopulated through famine, disease, and sustained military occupation. The prolonged nature of the conflict generated widespread political exhaustion among rulers and populations alike, eroding confidence in existing legal and institutional arrangements to restore peace or provide security (Croxton, 1999).

Medieval legal frameworks proved incapable of managing this crisis. Feudal obligations and religious norms offered no effective limits on warfare or intervention, while imperial institutions lacked the authority to enforce compliance. The absence of a shared legal understanding of political autonomy or jurisdiction meant that conflicts escalated without clear legal boundaries, revealing the inadequacy of inherited structures for regulating relations among increasingly autonomous political actors (Gross, 1948).

1.3 The need for a new legal settlement

By the mid-seventeenth century, the cumulative failure of feudal and religious hierarchies had become evident. Neither imperial authority nor ecclesiastical oversight could impose order or prevent recurrent conflict. The political landscape had shifted toward a reality in which multiple actors exercised de facto control over territories and populations, yet lacked a common legal framework to govern their coexistence. This disconnect between political practice and legal structure created persistent instability (Osiander, 2001).

There was growing demand for rules capable of stabilising relations among political entities without relying on universal authority. Rulers sought legal recognition of their autonomy, protection from external interference, and mechanisms to manage religious diversity within their domains. Peace required not only the cessation of hostilities but also a durable settlement that aligned legal principles with existing distributions of power (Teschke, 2003).

Diplomacy and multilateral negotiation emerged as essential tools for achieving this objective. The peace congresses at Münster and Osnabrück reflected a new approach to conflict resolution based on sustained negotiation, reciprocal commitments, and written agreements binding multiple parties. These practices signalled a shift toward treaty-based ordering of political relations and laid the groundwork for a more structured legal environment in Europe. The Westphalian settlement responded to these demands by translating political realities into formal legal arrangements capable of supporting a more stable interstate order (Bély, 2000).

2. The Treaty of Westphalia: Structure and Parties

2.1 The dual treaties of Münster and Osnabrück

The settlement commonly referred to as the Treaty of Westphalia consisted of two closely coordinated but legally distinct peace treaties, concluded on the same date in 1648. One treaty was negotiated and signed in Münster between the Holy Roman Emperor and the Kingdom of France, while the other was concluded in Osnabrück between the Emperor and the Kingdom of Sweden. Together, these instruments formed a single peace settlement ending the Thirty Years’ War, even though they addressed different parties, interests, and territorial adjustments (Croxton, 1999).

The separation of negotiations into two locations reflected both political necessity and religious sensibility. France, a Catholic power, insisted on negotiating in Münster, a Catholic city, while Sweden, a Protestant power, required negotiations to take place in Osnabrück, which had a Protestant majority. This geographical division allowed negotiations to proceed without forcing religious compromise on matters of diplomatic protocol, a concern that had repeatedly obstructed earlier peace efforts (Bély, 2000).

Despite being negotiated separately, the two treaties were legally interdependent. Provisions were carefully coordinated to avoid contradiction, and the instruments explicitly referenced one another to ensure coherence. This arrangement demonstrated an advanced level of diplomatic coordination and reflected an emerging practice of multilateral treaty-making in Europe. Peace was not imposed by a single authority but constructed through parallel agreements reflecting the plural nature of political power at the time (Wilson, 2009).

2.2 Principal subjects bound by the treaties

The primary subject bound by both treaties was the Holy Roman Emperor, acting not as a sovereign ruler of a unified state but as the head of a complex constitutional entity composed of multiple political units. Imperial authority was formally engaged in ending hostilities and recognising the legal positions of other actors within the Empire (Whaley, 2012).

German princes and imperial estates constituted another central category of treaty subjects. These included secular rulers, ecclesiastical authorities, and free imperial cities, many of which exercised substantial autonomy. The treaties confirmed their rights to govern internal affairs, particularly religious organisation, and recognised their capacity to enter alliances, subject to certain limitations. This acknowledgment reinforced their status as legally relevant actors within the imperial order, even though they were not sovereign states in the modern sense (Osiander, 2001).

France and Sweden emerged as external guarantors and beneficiaries of the settlement. Both powers secured territorial gains and political influence while also committing themselves to respecting the internal arrangements of the Empire. Their inclusion as principal treaty parties reflected the reality that the conflict had evolved into a European-wide war rather than a purely internal imperial matter (Parker, 1997).

The treaties also addressed the position of non-sovereign but autonomous actors. Ecclesiastical territories, imperial cities, and lesser estates were not independent states, yet they possessed recognised legal capacities within the imperial framework. The settlement preserved this layered political structure rather than replacing it with a uniform model of statehood. Legal personality was therefore distributed unevenly, based on historical privilege and political function rather than abstract equality (Gross, 1948).

2.3 Nature of the instruments under international law

From the standpoint of international law, the Westphalian instruments were peace treaties rather than constitutional charters. Their primary function was to terminate hostilities, restore order, and establish binding commitments among the parties. They did not purport to create a new legal system in abstract terms, nor did they articulate general principles applicable beyond the specific context of the settlement (Teschke, 2003).

The treaties created legal obligations through explicit consent. Each party accepted defined rights and duties, including territorial arrangements, religious guarantees, and non-interference commitments. These obligations were reciprocal, meaning that compliance by one party was conditioned on compliance by others. This structure reflected an early form of treaty-based legal ordering grounded in mutual recognition rather than hierarchical command (Berman, 1983).

Their binding force derived from agreement rather than moral or religious authority. Enforcement relied on political guarantees, alliance structures, and the shared interest in preventing renewed conflict. While modern mechanisms of international enforcement were absent, the treaties nevertheless contributed to a growing expectation that peace agreements created legal commitments capable of structuring future conduct among political entities (Croxton, 1999).

In legal terms, the significance of the Westphalian settlement lies not in constitutional innovation but in the consolidation of treaty practice as a central instrument for regulating relations among multiple actors. By embedding political compromise in binding legal texts, the settlement strengthened the role of consent, reciprocity, and written agreement as foundational elements of international legal relations.

3. Core Purposes of the Treaty of Westphalia

3.1 Termination of the Thirty Years’ War

A primary purpose of the Westphalian settlement was the formal and legally binding termination of the Thirty Years’ War. This objective was pursued through explicit treaty provisions declaring a permanent peace among the contracting parties and requiring the cessation of all military operations. The treaties imposed obligations on signatories to withdraw forces, end occupations, and refrain from supporting enemies of other parties, thereby translating political intent into enforceable legal commitments (Croxton, 1999).

Amnesty played a central legal role in consolidating peace. The treaties established a general and reciprocal amnesty covering acts committed during the conflict, including rebellion, confiscation, and collaboration with opposing forces. By legally extinguishing claims arising from wartime conduct, the settlement sought to prevent renewed conflict through litigation, reprisals, or dynastic retaliation. Amnesty functioned not as moral forgiveness but as a legal technique designed to reset political relations and stabilise authority across contested territories (Gross, 1948).

Restitution complemented amnesty by addressing the material consequences of prolonged warfare. The treaties provided detailed rules for the restoration of lands, titles, revenues, and political rights to their pre-war holders, subject to specified reference dates. These provisions aimed to reverse arbitrary wartime seizures and re-establish a predictable legal order grounded in recognised rights. Restitution was therefore instrumental in re-legitimising governance structures and reducing incentives for continued resistance or private violence (Whaley, 2012).

3.2 Stabilisation of political authority in Europe

Beyond ending hostilities, the settlement sought to stabilise political authority across Europe by aligning legal recognition with existing distributions of power. Rather than attempting to impose a uniform constitutional model, the treaties formally acknowledged the territorial control exercised by rulers and political entities at the conclusion of the war. This recognition reduced uncertainty over jurisdiction and reinforced the principle that authority would be exercised within defined territorial boundaries (Osiander, 2001).

The legal position of the Holy Roman Emperor was recalibrated. Imperial authority was preserved, but its scope was constrained by explicit recognition of the rights and autonomies of imperial estates. Princes and cities were confirmed in their internal governing powers, particularly in matters of religion and administration. This adjustment limited the capacity of the emperor to intervene unilaterally and reflected a shift toward a more decentralised legal order within the Empire (Wilson, 2009).

Equally significant was the reduction of external religious intervention. While the treaties did not eliminate the political influence of the papacy, they curtailed its role as a source of binding authority over secular rulers. Religious governance became a matter regulated within territories according to agreed legal rules rather than supranational decree. This change marked a decisive move away from universal religious jurisdiction as a basis for political intervention (Berman, 1983).

3.3 Creation of a durable framework for coexistence

The Westphalian settlement aimed to create conditions for durable coexistence among diverse political entities by prioritising balance over hierarchical control. The treaties rejected the idea that peace could be maintained through the dominance of a single universal authority, imperial or religious. Instead, stability was to be achieved through a distribution of power in which no actor could legitimately claim supremacy over others (Parker, 1997).

Mutual recognition served as the legal foundation of this framework. Political entities acknowledged each other’s authority and committed to respecting established rights and boundaries. Peace was grounded in reciprocal obligations rather than submission to a superior power. This approach reduced incentives for ideological or religious intervention and encouraged negotiation as the primary means of resolving disputes (Teschke, 2003).

The framework established in 1648 did not eliminate conflict, but it introduced legal expectations that shaped future conduct. Peace was conceived as a product of legal agreement among recognised actors, supported by diplomacy and treaty guarantees. This conception represented a significant departure from medieval models of order and contributed to the gradual development of a system in which coexistence depended on law-based recognition rather than claims of universal jurisdiction or divine mandate (Croxton, 1999).

4. Principal Legal Commitments and Rules

4.1 Territorial sovereignty

One of the most significant legal outcomes of the Westphalian settlement was the recognition of political authority as territorially defined. The treaties confirmed that rulers and political entities exercised governing power within identifiable territorial boundaries, and that this authority was to be respected by other parties. Governance was no longer framed primarily as a function of personal allegiance, dynastic claim, or religious mandate, but as a legal competence attached to control over territory (Osiander, 2001).

This territorialisation of authority carried important juridical consequences. Rulers were recognised as possessing exclusive jurisdiction over administrative, legal, and religious matters within their domains. External actors, including the emperor and foreign powers, were legally constrained from intervening in internal affairs absent specific treaty rights. Territorial boundaries thus became the spatial limits of lawful political authority, providing a clearer framework for allocating jurisdiction and responsibility (Whaley, 2012).

The recognition of territorial authority did not eliminate overlapping claims overnight, nor did it establish absolute sovereignty in the modern sense. Imperial law and customary privileges continued to shape governance within the Holy Roman Empire. Even so, the treaties reinforced a decisive shift toward territorial jurisdiction as the organising principle of political power, a development that would later become central to public international law (Skinner, 1978).

4.2 Religious settlement and internal autonomy

Religious governance formed a core component of the Westphalian legal settlement. The treaties reaffirmed the principle commonly expressed as cuius regio, eius religio, under which rulers retained authority to determine the official religion of their territories, subject to agreed protections for minority confessions. This confirmation was legally significant because it transformed a contested political practice into a treaty-based rule accepted by multiple parties (Berman, 1983).

The settlement established fixed reference dates for determining lawful religious possession of churches, lands, and offices. By anchoring religious arrangements to specific points in time, the treaties sought to prevent continuous revision through force or coercion. These provisions reduced incentives for religious intervention by external actors and limited the use of confessional allegiance as a legal justification for interference (Wilson, 2009).

Internal religious autonomy was therefore legally protected within territorial boundaries. While the settlement did not establish freedom of religion in the modern sense, it curtailed claims of universal religious authority over secular governance. Religious disputes were reclassified as internal matters governed by treaty rules rather than as grounds for external enforcement, reinforcing the broader movement toward territorially bounded authority (Gross, 1948).

4.3 Legal equality of political entities

The treaties affirmed a form of legal equality among political entities participating in the settlement. Imperial estates, secular princes, ecclesiastical rulers, and free cities were recognised as holders of rights and obligations under the peace agreements. This recognition did not imply equal power or status in practice, but it did establish that no entity could claim inherent legal superiority based on universal authority (Osiander, 2001).

This formal equality was particularly evident in the rejection of claims to universal temporal supremacy. Neither the emperor nor the papacy was acknowledged as possessing overarching authority to dictate political arrangements across Europe. Political entities were treated as legally autonomous within their recognised competences, bound by mutual obligations rather than subordination to a higher secular or religious power (Teschke, 2003).

The legal effect of this arrangement was to normalise coexistence among multiple actors without a single apex authority. Legal personality and capacity were distributed across a plural system, laying the groundwork for later doctrines of sovereign equality among states. Although far removed from contemporary formulations, this development represented a decisive move away from hierarchical legal ordering (Parker, 1997).

4.4 Non-intervention in domestic affairs

Closely linked to territorial authority and legal equality was the principle that external actors should refrain from intervening in the internal affairs of other political entities. The Westphalian treaties did not articulate a general doctrine of non-intervention, yet their provisions limited lawful interference in governance, religion, and administration within recognised territories. These constraints functioned as an early legal expression of what would later become a core principle of international law (Gross, 1948).

In practical terms, this meant that rulers could no longer invoke religious solidarity, imperial prerogative, or dynastic allegiance as automatic justifications for intervention. Military assistance, political pressure, and administrative interference were restricted by treaty commitments and reciprocal guarantees. Violations risked collective response or renewed conflict, creating incentives for restraint (Croxton, 1999).

The diplomatic implications were substantial. Political disputes increasingly required negotiation rather than unilateral action, and treaty obligations became reference points for assessing lawful conduct. While intervention did not disappear from European politics, the legal framing of such actions began to change, marking an important step toward a system in which domestic affairs were presumptively shielded from external coercion (Wilson, 2009).

5. Westphalia and the Concept of Sovereignty

5.1 What sovereignty meant in 1648

At the time of the Westphalian settlement, sovereignty was understood primarily as independence from external authority rather than as unlimited or absolute power. Political entities sought recognition that no superior secular or religious authority could lawfully dictate their internal governance. Sovereignty functioned as a claim to autonomy in decision-making, especially in matters of religion, administration, and alliance, rather than as a comprehensive monopoly over all aspects of political life (Skinner, 1978).

This understanding of sovereignty was inseparable from territory. Authority was increasingly associated with control over a defined geographical space, within which rulers exercised jurisdiction over people, resources, and institutions. Territorial control provided the practical foundation for political independence, allowing rulers to enforce decisions and exclude external interference. The Westphalian settlement reinforced this connection by recognising authority as spatially bounded and legally protected within agreed borders (Whaley, 2012).

Sovereignty in 1648, therefore, remained constrained and contextual. Imperial law, customary privileges, and treaty obligations continued to limit the exercise of power. Even so, the settlement marked an important step in aligning legal authority with territorial governance, strengthening the expectation that political independence would be exercised within defined spatial limits rather than through overlapping personal or religious claims (Osiander, 2001).

5.2 What Westphalia did not establish

Despite its later symbolic status, the Westphalian settlement did not create nation-states in the modern sense. Political authority continued to rest largely on dynastic rule, hereditary titles, and composite polities rather than on popular sovereignty or national identity. Many entities recognised under the treaties governed culturally and linguistically diverse populations without any notion of a unified nation (Teschke, 2003).

The settlement also did not codify a general prohibition on the use of force. Warfare remained a recognised instrument of policy, and armed conflict continued to shape European politics after 1648. The treaties imposed specific obligations to end hostilities among the parties and to respect agreed arrangements, but they did not articulate a universal legal rule banning war as such. The regulation of force would only emerge gradually through later practice and legal development (Parker, 1997).

Dynastic and imperial politics persisted well beyond the seventeenth century. Succession disputes, territorial claims, and balance-of-power calculations continued to drive conflict. The Holy Roman Empire retained its constitutional structure, and imperial institutions remained relevant within their reduced sphere. The significance of the settlement lies not in replacing these dynamics, but in legally accommodating them within a more stable framework of territorial autonomy and mutual recognition (Wilson, 2009).

5.3 Contribution to later doctrinal development

The Westphalian settlement exerted a lasting influence on the evolution of international legal doctrine by shaping how sovereignty and political authority were conceptualised by later jurists. Classical writers of international law, including Grotius, Pufendorf, and Vattel, drew upon the emerging practice of territorially defined independence and reciprocal recognition when articulating principles governing relations among states (Berman, 1983).

These thinkers did not treat the settlement as a theoretical foundation, but as evidence of changing political reality. Sovereignty was increasingly framed as a legal condition grounded in independence and jurisdiction, rather than as a theological or imperial attribute. Treaty practice following 1648 reinforced this shift, as agreements routinely assumed the existence of autonomous political entities capable of binding themselves through consent (Gross, 1948).

Over time, repeated state practice consolidated these ideas into more general legal principles. Territorial integrity, jurisdictional exclusivity, and legal equality evolved through cumulative application rather than formal declaration. The Westphalian settlement contributed to this process by aligning legal commitments with political autonomy, helping to normalise sovereignty as a defining feature of international legal personality. Its doctrinal legacy lies in this gradual consolidation rather than in any single legal innovation (Osiander, 2001).

6. Legal and Practical Effects After 1648

6.1 Transformation of diplomatic relations

The Westphalian settlement accelerated a transformation in diplomatic practice that had begun earlier but lacked a stable legal foundation. Relations among political entities increasingly relied on continuous diplomatic engagement rather than ad hoc envoys dispatched during crises. Permanent diplomatic missions became more common, reflecting the recognition that political entities were enduring actors whose relations required ongoing management rather than episodic negotiation (Berridge, 2010).

Multilateral congresses also gained legitimacy as instruments for addressing collective problems. The peace negotiations at Münster and Osnabrück demonstrated that complex conflicts involving multiple actors could be resolved through sustained, coordinated diplomacy rather than unilateral settlement or imperial decree. This experience influenced later European congresses, reinforcing negotiation and treaty-making as central mechanisms for maintaining order among autonomous political entities (Bély, 2000).

These developments were closely tied to the consolidation of states and state-like entities as primary legal actors. Political authority was increasingly exercised and recognised through institutions capable of concluding treaties, maintaining diplomatic representation, and assuming legal obligations. This shift strengthened the role of consent-based agreements in structuring political relations and reinforced the expectation that disputes would be addressed through diplomatic channels rather than through immediate recourse to force (Osiander, 2001).

6.2 Impact on the Holy Roman Empire

Within the Holy Roman Empire, the legal effects of the Westphalian settlement were profound. German princes and imperial estates emerged with enhanced autonomy over internal governance, particularly in religious, administrative, and fiscal matters. Their authority to conduct certain external relations, including alliances, was acknowledged within defined limits. This recognition formalised a level of independence that many estates had already exercised in practice, reducing legal uncertainty surrounding their status (Whaley, 2012).

The central authority of the emperor was correspondingly weakened. While imperial institutions continued to exist, their capacity to impose uniform policies across the Empire was constrained by treaty-based guarantees of territorial autonomy. Imperial intervention now required legal justification consistent with the settlement, limiting unilateral action and reinforcing decentralisation within the imperial structure (Wilson, 2009).

The Empire thus evolved into a more explicitly plural legal order. Rather than functioning as a centralised sovereign entity, it operated as a framework accommodating multiple autonomous actors bound together by shared legal commitments. This arrangement preserved imperial continuity while acknowledging political realities shaped by territorial governance and local authority (Osiander, 2001).

6.3 Long-term effects on the European order

At the European level, the settlement contributed to the emergence of a balance of power system grounded in mutual restraint and legal recognition. No single political entity could plausibly claim universal authority, and stability depended on maintaining equilibrium among competing powers. Legal commitments reinforced this balance by embedding political compromises in treaty form and discouraging unilateral revision through force (Parker, 1997).

The Westphalian agreements also provided a practical model for later peace settlements. Subsequent treaties increasingly relied on similar techniques: recognition of territorial control, reciprocal guarantees, amnesty provisions, and multilateral negotiation. These elements became standard features of European peace-making, shaping expectations about how conflicts should be resolved and how political authority should be stabilised after war (Croxton, 1999).

Over time, this pattern contributed to a more predictable legal environment in which political entities understood both their rights and their limits. Conflict did not disappear, yet it became increasingly framed within a legal context shaped by treaty obligations and diplomatic practice. The enduring impact of the Westphalian settlement lies in its role in normalising law-based coexistence among autonomous actors within a plural European order (Berman, 1983).

7. Concrete Application Example

7.1 Territorial authority and non-intervention in practice

A clear illustration of how the Westphalian settlement operated in practice can be seen in the recognition of a territorial ruler’s exclusive authority over religious and administrative matters within his domain. German princes were legally confirmed in their right to organise religious life, appoint officials, and regulate public order without external interference, provided their actions conformed to the treaty’s agreed religious arrangements. This recognition transformed what had previously been contested political practice into a legally protected competence grounded in treaty obligation (Whaley, 2012).

For example, a Protestant prince governing a defined territory within the Holy Roman Empire could lawfully determine the public exercise of religion and manage ecclesiastical property according to the settlement’s reference dates. External Catholic powers, including the emperor acting beyond treaty limits or foreign rulers invoking confessional solidarity, were legally constrained from intervening on religious grounds alone. Interference that disregarded these arrangements could be framed as a breach of the peace settlement rather than as the enforcement of religious orthodoxy (Wilson, 2009).

These constraints had practical legal consequences. Diplomatic protests, alliance guarantees, and collective pressure could be mobilised against violators of territorial authority. While enforcement mechanisms remained political rather than judicial, the legal framing altered how disputes were justified and contested. Intervention required treaty-based justification rather than appeals to universal religious or imperial authority, reinforcing the expectation that internal governance fell within the protected sphere of territorial rule (Osiander, 2001).

7.2 Influence on later peace treaties

The legal logic embedded in the Westphalian settlement exerted a lasting influence on subsequent European peace treaties. Later agreements increasingly relied on territorial settlement as a means of restoring stability after conflict. Boundaries were recognised, authority was allocated according to control over territory, and political compromise was formalised through written agreements binding multiple parties. These techniques reflected the Westphalian emphasis on legal recognition of existing power arrangements as the basis for peace (Croxton, 1999).

Peace settlements in the eighteenth century routinely incorporated similar mechanisms. Territorial adjustments were accompanied by mutual recognition of authority, amnesty provisions, and guarantees against interference. Rather than attempting to impose ideological or religious uniformity, treaties prioritised stability through legal acknowledgment of plural political realities. This approach reduced incentives for renewed conflict by aligning legal order with political fact (Parker, 1997).

Territorial settlement thus became a central tool for managing European order. Legal recognition of authority within defined borders offered a practical method for containing disputes and limiting escalation. Although conflicts persisted, the reliance on treaty-based territorial arrangements reflected a durable legacy of the Westphalian approach to peace-making. Its influence is evident in the continued use of negotiated territorial compromise as a stabilising mechanism in European diplomatic practice well beyond the seventeenth century (Berman, 1983).

8. The “Westphalian System”: Myth and Reality

8.1 Origins of the Westphalian narrative

The idea of a distinct “Westphalian system” emerged largely in nineteenth- and twentieth-century scholarship rather than from contemporaneous interpretations of the 1648 settlement. As international law developed as a formal academic discipline, scholars sought historical reference points that could explain the transition from medieval hierarchy to a system of territorially defined political entities. The Westphalian peace, with its emphasis on territorial authority and mutual recognition, offered a convenient focal moment for this narrative (Gross, 1948).

Legal historians and political theorists increasingly portrayed the settlement as the birth of modern international law and the sovereign state system. This framing aligned with the needs of a discipline attempting to explain its own foundations and coherence. Westphalia came to symbolise a decisive break with religious universalism and imperial supremacy, even though the treaties themselves did not articulate such a transformation in abstract or systematic terms (Osiander, 2001).

Over time, the narrative hardened into a simplified account in which 1648 marked a clear legal rupture. The complexity of early modern political arrangements and the gradual nature of legal change were often compressed into a single moment of origin. As a result, Westphalia acquired a status that exceeded its historical and doctrinal content, functioning as a shorthand explanation for the emergence of the modern international order (Teschke, 2003).

8.2 Scholarly critiques

Critical scholarship has challenged this narrative on both historical and legal grounds. One central argument is that sovereignty and territoriality were not invented in 1648. Forms of territorial rule, jurisdictional authority, and political independence existed well before the seventeenth century. Medieval kingdoms exercised territorial governance, and early modern rulers asserted autonomy long before the Westphalian negotiations took place (Skinner, 1978).

Another line of critique highlights the anachronism involved in projecting modern legal concepts onto early modern treaties. The settlement did not articulate doctrines of sovereign equality, exclusive jurisdiction, or non-intervention in the form later codified in international law. Political entities continued to operate within dynastic, imperial, and confessional frameworks that differ markedly from contemporary legal understandings of statehood (Osiander, 2001).

Scholars have also pointed out that post-1648 Europe remained deeply hierarchical in practice. Power disparities, imperial institutions, and religious influence persisted, and warfare remained a central feature of political life. Treating Westphalia as the origin of a fully formed international legal system risks obscuring the continuity of older practices and the incremental nature of legal development (Wilson, 2009).

8.3 Why Westphalia still matters despite criticism

Despite these critiques, the Westphalian settlement retains significant analytical value. Its importance lies not in having created modern international law ex nihilo, but in consolidating existing practices into a mutually accepted legal framework. The treaties translated political realities into binding legal commitments, reinforcing expectations about territorial authority, autonomy, and reciprocal obligation among political entities (Croxton, 1999).

Westphalia also holds enduring symbolic significance. It represents a moment when peace was achieved through multilateral negotiation rather than unilateral imposition, and when legal agreement replaced claims of universal authority as the basis for political order. This symbolism continues to shape how international law conceptualises legitimacy, consent, and coexistence among diverse actors (Berman, 1983).

The settlement is best understood as a consolidation point rather than a starting point. It aligned legal rules with evolving political practice and provided a reference framework that later generations could build upon. Even as its mythologised status is questioned, its structural contribution to the development of a territorially grounded legal order remains central to understanding the evolution of public international law (Osiander, 2001).

Also Read

• The Peace of Westphalia and International Relations

• Law and Force in the Twenty-First Century

• The Practice of International Law

• The Age of Grotius: Foundations and Impact on International Law

• The Struggle for an International Constitutional Order

• International Law and the International Community: Dynamics, Challenges, and Evolution

9. Contemporary Relevance of the Treaty of Westphalia

9.1 Sovereignty in a globalised legal order

The contemporary international legal order operates in conditions radically different from those of the seventeenth century, yet the core idea of territorially grounded political authority consolidated in 1648 continues to shape legal reasoning. Sovereignty today exists within a dense network of international obligations, including human rights treaties, economic regimes, and environmental agreements. States remain the primary holders of legal authority, but their freedom of action is conditioned by consent-based commitments that regulate how power may be exercised within their territories (Crawford, 2019).

International organisations further complicate the exercise of sovereignty. Membership in bodies such as the United Nations entails acceptance of institutional decision-making processes that may influence domestic policy. Even so, participation is grounded in state consent, and withdrawal remains legally possible. This reflects a continuity with the Westphalian logic of autonomy constrained by voluntarily assumed obligations rather than by imposed hierarchy (Koskenniemi, 2005).

Human rights law illustrates this interaction clearly. States retain jurisdiction over their populations, yet they are subject to international scrutiny and accountability mechanisms. These regimes do not eliminate sovereignty but reshape its exercise by imposing legal standards on internal governance. Territorial authority remains the basis of responsibility, demonstrating the continued relevance of territorially defined jurisdiction as a foundational legal concept (Shaw, 2021).

9.2 Non-intervention and modern conflicts

The principle that external actors should refrain from interfering in domestic affairs remains a central element of diplomatic discourse. Modern debates surrounding humanitarian intervention, responsibility to protect, and counterterrorism operations frequently reference the limits of lawful intervention. States continue to invoke territorial authority and political independence as shields against external coercion, drawing upon legal reasoning that echoes the constraints articulated in early treaty practice (Chesterman, 2001).

At the same time, contemporary conflicts reveal tensions within this framework. Claims of intervention justified by human rights protection or collective security challenge traditional understandings of non-interference. These debates do not reject territorial sovereignty outright but reinterpret its scope in light of competing legal obligations. The persistence of such arguments demonstrates that the core issue addressed by the Westphalian settlement—how to reconcile autonomy with coexistence—remains unresolved (Bellamy, 2010).

Diplomatic practice continues to rely on legal justification rather than unilateral assertion. Even when intervention occurs, it is framed as exceptional and legally grounded, indicating that non-intervention retains normative force. This reliance on legal argument reflects the enduring influence of a system in which authority within territory is presumptively protected, and external interference requires explicit justification (Corten, 2016).

9.3 Enduring influence on public international law

The structural influence of the Westphalian settlement is evident in contemporary international law, particularly in principles enshrined in the United Nations Charter. Territorial integrity and the legal equality of states remain foundational norms governing international relations. These principles reflect a long-standing commitment to territorially defined authority and reciprocal recognition among political entities (Shaw, 2021).

Even as international law has expanded into new domains, the state remains the central legal subject. Jurisdiction, responsibility, and enforcement are still primarily organised around territorial control. This continuity underscores the settlement’s role as a historical anchor that shaped the basic architecture of the legal order rather than as a detailed template for modern governance (Crawford, 2019).

The relevance of the Westphalian settlement, therefore, lies in its structural legacy. It provided a framework within which political authority, legal obligation, and territorial jurisdiction could be aligned. Contemporary international law has evolved far beyond the conditions of 1648, yet it continues to operate within boundaries defined by territorial sovereignty and consent-based legal ordering. Westphalia remains a reference point for understanding how these foundational concepts emerged and why they continue to frame debates about authority, intervention, and coexistence in international law.

Conclusion

The Treaty of Westphalia occupies a central position in the legal history of international relations because it translated political necessity into binding legal form. Its core legal significance lies in the consolidation of territorially defined authority, the recognition of political autonomy grounded in control over territory, and the articulation of reciprocal obligations among multiple actors without reliance on universal secular or religious supremacy. By embedding these elements in treaty commitments, the settlement provided a durable legal response to the structural failures that had produced prolonged conflict in early modern Europe.

The settlement reshaped interstate relations by aligning legal recognition with political reality. Authority was no longer justified primarily through dynastic lineage or religious mandate, but through governance exercised within defined territorial limits. This shift reinforced the expectation that political entities would respect each other’s internal competence and manage their relations through diplomacy and agreement rather than through claims of superior authority. Territorial sovereignty, understood as independence from external control rather than absolute power, emerged as a stabilising principle capable of supporting coexistence among diverse actors.

At the same time, the Westphalian settlement should not be treated as a comprehensive blueprint for the modern international legal order. It did not create nation-states, prohibit war, or eliminate hierarchy and power asymmetry. Dynastic politics, imperial structures, and armed conflict persisted long after 1648. Its importance lies not in exhaustive regulation or normative completeness, but in its function as a foundational consolidation of evolving legal practice.

Viewed within the broader evolution of public international law, Westphalia represents a decisive moment in which territorial authority, consent-based obligation, and legal equality were brought into closer alignment. These elements would later be refined, expanded, and reinterpreted through centuries of treaty practice, doctrinal development, and institutional growth. The settlement remains neither obsolete nor omnipotent, but foundational: a historical anchor that helps explain how modern international law came to be structured around states, territory, and legally defined coexistence.

References

1. Bély, L. (2000) The Peace of Westphalia (1648). London: Macmillan.

2. Bellamy, A.J. (2010) Responsibility to Protect: The Global Effort to End Mass Atrocities. Cambridge: Polity Press.

3. Berman, H.J. (1983) Law and Revolution: The Formation of the Western Legal Tradition. Cambridge, MA: Harvard University Press.

4. Berridge, G.R. (2010) Diplomacy: Theory and Practice. 4th edn. Basingstoke: Palgrave Macmillan.

5. Chesterman, S. (2001) Just War or Just Peace? Humanitarian Intervention and International Law. Oxford: Oxford University Press.

6. Corten, O. (2016) The Law Against War: The Prohibition on the Use of Force in Contemporary International Law. Oxford: Hart Publishing.

7. Crawford, J. (2019) Brownlie’s Principles of Public International Law. 9th edn. Oxford: Oxford University Press.

8. Croxton, D. (1999) ‘The Peace of Westphalia of 1648 and the Origins of Sovereignty’, The International History Review, 21(3), pp. 569–591.

9. Gross, L. (1948) ‘The Peace of Westphalia, 1648–1948’, American Journal of International Law, 42(1), pp. 20–41.

10. Koskenniemi, M. (2005) From Apology to Utopia: The Structure of International Legal Argument. Cambridge: Cambridge University Press.

11. Osiander, A. (2001) ‘Sovereignty, International Relations, and the Westphalian Myth’, International Organization, 55(2), pp. 251–287.

12. Parker, G. (1997) The Thirty Years’ War. 2nd edn. London: Routledge.

13. Shaw, M.N. (2021) International Law. 9th edn. Cambridge: Cambridge University Press.

14. Skinner, Q. (1978) The Foundations of Modern Political Thought, Volume II: The Age of Reformation. Cambridge: Cambridge University Press.

15. Teschke, B. (2003) The Myth of 1648: Class, Geopolitics, and the Making of Modern International Relations. London: Verso.

16. Whaley, J. (2012) Germany and the Holy Roman Empire, Volume I: Maximilian I to the Peace of Westphalia, 1493–1648. Oxford: Oxford University Press.

17. Wilson, P.H. (2009) Europe’s Tragedy: A History of the Thirty Years’ War. London: Allen Lane.