The Old Regime period in which war proved the norm and peace the exception witnessed the development of the modern law of nations. Questions of international law assumed a new urgency as did the status of diplomatic agents. By this time the existence of permanent embassies could still be deplored but no longer questioned, and diplomatic immunity could not be disputed, reinforced as it was by a body of precedent and tradition. This period witnessed first the expansion and later the contraction of diplomatic privilege. European aristocratic society reinforced diplomatic privilege, for the status of the ambassador was inextricably intertwined with that of the ruler. The explosive expansion of diplomats and their staff led many theorists, such as Grotius and Vattel, to analyse the evolving conventions, such as the importance of the civil immunity of the ambassador and the liability of the embassy staff. Practice tended to reinforce privileges identified as personal, that is, attached to the ambassador himself. Of these the exemption from criminal liability was perhaps the most important. Among territorially defined privileges, the right of asylum and the notorious right of quarter were first expanded and later either limited or eliminated.

In Renaissance Europe, war and the use of force were regular phenomena and likewise subject of common rules. The theory of ‘just war’, dating back to ancient times, was further developed by legal scholars, and all belligerents claimed to have a just cause, often explained in printed pamphlets. International law consisted of theory and practice, and thus, they should be considered in a mutual context. The focus was still on the question of who had a right to wage war, i.e. on the jus ad bellum, and barely on regulations of warfare or on a containment of war. International law in Renaissance Europe rooted in its very society, in its rules and values. Legal debates and war justifications consolidated the Christian European community, which even in war times did not break apart, even if it was contradictory to the principle of sovereignty and the idea that a sovereign owes no justification to anyone. Moreover, scholars and belligerents argued with natural law and insisted in the universality of international law, although it was in fact basically European. Thus, in Renaissance Europe well-established traditions existed for how to handle war, but they were more and more challenged by the idea of sovereignty, as well as by the European expansion and by global interaction.

This chapter describes territorial conflicts among lords, parishes, cities and towns, and how they contributed to emerging notions of the territoriality of states. It surveys debates regarding both the expansion to new territories and the conservation of existing territories and considers how these debates operated both in Europe and in European overseas colonies. It analyses the writing of jurists as well as a plethora of practices that contemporaries pursued, which despite their obvious local reiterations, were mostly pan-European. Among other things, it covers the question of just war, taking possession of not yet occupied land, discovery, prescription, conservation of the status quo and the role of both conflicts and agreements, including agreements with indigenous peoples, natural law, the law of nations and of relations between territory and jurisdiction. To explain developments during the Renaissance, it observes a much longer time span that began in the Middle Ages and allowed for both slow and revolutionary transformations. It shows that developments in Europe were important, but as vital in both encouraging and empowering change was colonialism, which affected many peoples and territories across the world but also modified Europe in ways we have not yet completely understood.

This chapter is a survey of the legal languages used to govern territory, sovereignty and the right of a ruler within a polity. Debates were heavily dominated by feudal and private law-concepts. Sovereigns maintained the diversity of privileges in the territories ruled in the setting of a composite monarchy. Claims and titles could or could not entail consequences for sovereignty. Reservations and exceptions to full internal sovereignty were not uncommon. Succession quarrels (often causes of war), could be solved by treaty, often in conflict with domestic constitutional rules and principles. Mixed polities (Poland-Lithuania, Holy Roman Empire) offered a broad range of argumentative topoi to either confirm or combat overlordship. Internal German questions could quickly escalate to the field of the law of nations through the game of alliances and guarantees. Although republican forms of monarchy and republican oligarchies were on the decline in the seventeenth and eighteenth centuries, their legal agency was not contested. In extra-European dominions of European sovereigns, the chain of reasoning was significantly lighter, as feudal arguments rarely came into play. Conversely, the agency of subaltern actors in establishing boundaries, or the treatment of native Americans as either allies or subjects provide original avenues of research.

The chapter gives an overview of dispute settlement during the Old Regime. Contrary to older assessments of the historiography, dispute settlement retained its importance in this era, both in qualitative and in quantitative terms. This was true for the field of theoretical literatures, which, from the last decades of the seventeenth century, dealt intensively with the subject. Normally, a clear distinction was made between an elected arbiter, who definitively decided a dispute, and a mediator, who only made peace proposals. Diplomatic practice, which made intensive use of the instruments of dispute settlement until the last decades of the eighteenth century, was much more flexible. The transitions between arbitration and mediation were fluid; the boundaries of confession and rank were also frequently crossed. In Old Regime Europe, mediation was also used for the first time in peace negotiations between Christian and Islamic powers. New forms of mediation emerged as well. One was the armed mediation, in which a power intervened in a conflict uninvited and set a peace ultimatum; this could easily lead to war. This indicates that dispute settlement did not automatically contribute to an increase in peace; the relationship of dispute settlement to war and peace remained rather ambivalent in Old Regime Europe.

This chapter charts the profound transformations undergone by diplomacy, both secular and papal, in an age of dramatic intellectual, political and military upheaval. Considering both scholarship and practice, the chapter assesses the rise of ‘resident diplomacy’ and highlights the new structures that were put in place in order to manage longer missions. The investigation of the right to send ambassadors reveals persistent traits of pluralism in early modern Europe, while the plurality of diplomatic envoys and roles is taken into account to make the complexity of the notion of diplomatic status more apparent: this status, in fact, cannot be reduced to that of a fully fledged ambassador exclusively committed to the object of their official mission. Information-gathering, negotiation and mediation are singled out as the most significant diplomatic functions. Changes in the conception of diplomatic inviolability and immunity are also considered, and include the emergence of the idea of extraterritoriality concerning both the person of the ambassador and diplomatic premises.

The Ottomans had a variety of ways of dealing with non-Muslim foreigners. In theory, Islamic law assumed a constant state of war between Muslim and non-Muslim rulers, but in practice, long-term peace arrangements were possible and even common. In terms of diplomacy, the Ottomans’ instruments and peacemaking procedures were similar to those of the West, the Turks likewise building on established customs and practices from the Byzantine period and beyond. The ahdnames were particularly important for international relations; originally unilateral documents, they evolved into more reciprocal instruments, only to become more unilateral again in the second half of the seventeenth century. In theory, peace with unbelievers should be temporary, but in practice, the duration of treaties concluded by the Ottomans reflected their assessment of the likelihood of hostilities resuming; in the case of countries that did not pose any military threat to the sultan’s domains, peace could even be concluded indefinitely. As long as both sides maintained the friendship between the two parties, there was no need to fear the Turks. The interconnected phenomena of slavery and privateering regularly put a strain on this friendship, as men, women and children on both sides were dragged off and sold as chattel. This loss of life and property sometimes led to international incidents, in which the Ottoman authorities made it clear that the basic Islamic parameters of peace could not be ignored with impunity.

The question of whether or not the sea can be owned or controlled has occupied the minds of many over the centuries. The discovery of America by Columbus made the questions of ownership of the sea and how regimes to govern the sea could be created and managed gain importance on a global scale. This chapter discusses the history of the law of the sea from the perspective of ‘Renaissance Europe’, focusing on the ‘battle of the books’ dominated by the publication of Mare Liberum (1609) by Hugo de Groot (Grotius) and John Selden’s Mare clausum (1635). It shows that the concept of the free sea was perfectly compatible with the adjacent or territorial sea both in legal practice and in principle. The idea of the free sea, defended and made explicit by Grotius, was not new but originated in Roman law and its medieval interpretations. Rather than the free sea, mare clausum was the new contribution of early modern thinking on the law of the sea. The concept of mare clausum had been shaped by the division of the world’s oceans between Spain and Portugal based on the papal bull Inter Caetera (1493) and the treaties of Tordesillas (1494) and Zaragoza (1529).

The sixteenth and early seventeenth centuries marked a deep crisis of the international political and legal order of Europe, caused by the Reformation, the emergence of some strong composite monarchies and the discovery of the New World. The chapter maps how the law of nations began to emerge as a new paradigm for the governance of Europe under whose wings rulers, diplomats and scholars attempted to advance claims to an exclusive jurisdiction over international relations by sovereign princes and republics. As such, the ‘law of nations’ functioned as a lever, an argument for power in a period of great clashes between centralising governments, opposing confessions, and regional and local elites, rather than representing a reality. The ultimate success by governments in several important states at the end of the Renaissance was facilitated to a great extent by the patrimonial and transactional nature of the states that allowed to include old, autonomous powers in the machinery of state.

The present chapter addresses the creation process of the fundamental dichotomic system of the modern law of the sea, viz. territorial sea and high seas, in Old Regime Europe thorough the analyses of ‘state practices’ and doctrines regarding dominium maris, based on some preceding historical backgrounds. It also discusses two neglected issues in order to grasp the accurate, at least theoretically, traces in establishing the current perception of ‘territorial sea’ emanating from the ‘cannon-shot rule’, most famously propounded by Bynkershoek for defining the outer limit of the adjacent sea. The discussion concludes that, although the basic notion of the modern dichotomic system had generally been recognised during the epoch surveyed, no unified criterion for determining the extent of the terrestrial authority over the sea had emerged. It suggests, in the end, the importance of two Italians, Galiani and Azuni, as the earliest known theorists who proposed the theoretical equation of the rules of cannon-shot and three-mile limit and indicates the necessity of fathoming the complex spoors of the history of the law of the sea originating from immensely diverse theories and practices.

The chapter examines the development and changing nature of the laws and customs of war in Old Regime Europe. It focuses on land warfare, scrutinising the received idea that the waging of war in this age was characterised by a growing moderation and by the improvement of troops’ conduct and discipline. The chapter surveys the major principles and doctrines of the jus in bello and the use thereof made by European players. In doing so, it draws on state and military practice as well as scholarly – legal and military – literature. Subjects which are covered include the theoretical conceptualisation of the laws of war, status in war and neutrality – limited to its terrestrials aspects – the emergence of new legal constraints regarding the treatment of prisoners of war and civilians, siege warfare and use of weapons, the treatment of enemy possessions and occupation.

Between the mid-fifteenth and mid-seventeenth centuries, norms on maritime warfare by both private and public actors developed through the intensification of maritime trade networks, European colonial and commercial expansion in other continents, the growing ascendancy of the sovereign state, and the emergence of a distinctive legal scholarship on topics of the law of nations. Although even among European political actors, there was still no general consensus on precise and binding norms governing maritime warfare, the building stones of a normative framework were gradually established which would be integrated from the later seventeenth century onwards into a more consistent body of international law. Prize courts played a crucial role in promoting the principles of such a legal framework, as did state practice on key issues such as blockade, contraband and neutrality.

In the great treatises of Gentili and Grotius, the law regulating the ending of war and the restoration were discussed as the third, chronological and logical part of the laws of war. Their conceptualisation of peace was premised on their conceptualisation of war either as an instrument for the vindication of justice or as the settlement of disputes about right. The chapter explains how these theories, and in particular the latter conception, reflected the practices of peacemaking in peace treaties well, focusing on such major issues as the temporal and spatial dimensions of peace, territorial disputes and the place of communitarian interests in a logic that was geared towards the settlement and appeasement of bilateral disputes over dynastic rights.

This chapter explores the justification and legitimisation of war and ‘imperfect’ uses of force both in legal scholarship and diplomatic practice. The Grotian synthesis of ‘just’ and ‘formal’ war entered mainstream scholarship and reached its full explanatory force in the work of Vattel. The resilience of just war in the face of its impracticality among sovereign state in scholarship can, among other, be explained by the fact that the subtle interplay of two conceptions of law in fields of legal application - , gelled well with diplomatic practice. Whereas states applied the jus in bello and jus post bellum with regards to claims to the justice of the war, the just war doctrine remained a common discourse for the justification of resort to war and force and added an instrument to the toolbox of alliances diplomacy.

The Old Regime period saw the highpoint of the role of peace treaties in the political and legal ordering of Christian Europe. Whereas the peace instrument by and large continued to adhere to the legal logic of the settlement of disputes about right between pairs of belligerents, important peace treaties entered into the constitutional fabric of Europe through the workings of multilateral alliances and general peace conferences and through the networking of treaties in different fashions. The encompassing nature of warfare also led to a phase of the growth of the length and legal complexity of peace treaties, particularly during the seventeenth century. The eighteenth century in turn saw a trend towards the standardisation of peace treaty clauses, marking the emergence of an elaborate body of peacemaking lore, or even law.

In this period, states strove for more control over their international trade routes. However, this was a matter of ideology and planning rather than a reality. Trades were still mainly supervised by chartered companies. States increasingly aimed to restrict exports of their colonial goods to other countries. However, their ‘mercantilist’ approaches did not yield the results that were expected. In attempts to reduce smuggling, private trade became acknowledged more. An aim of consolidating and perfecting colonial trade had more impact in Asia than in the Caribbean. There, geopolitical contexts as well as features of crops precluded strict control. Compared to the previous period, international trade law consisted mostly of treaty law. Some clauses, such as the most-favoured-nation clause, could be opted for in many treaties. Legal borrowing happened, for example, with regard to governance structures in colonial territories, but there was no harmonised law of international trade. Domestic legislation was combined with treaties. Ius gentium doctrine mainly focused on a right of trade. In the later eighteenth century, views of this type were combined with ideas of self-reliance of the economy. Over the course of the seventeenth and eighteenth centuries, financial markets had become a factor that policy-makers had to take into account. Because of the growing intertwining of state finance, colonial trade and speculation at stock markets, the risk of bubbles rose.

The sixth volume in The Cambridge History of International Law covers the developments of inter- and transnational laws in early modern Europe (1492–1660). The preface explains how recent revisionism of traditional state- and Eurocentric views on the history of international law impacts the study of this subject and how this is reflected in the volume.

This chapter offers a discussion on the laws of war, or jus in bello, as the previous one. However, it provides an exclusive focus on maritime warfare. Old Regime Europe was marked by the expansion of permanent state battlefleets and the strengthening of naval administrations. At the same time, a complementarity between public and private forms of maritime warfare, notably privateering, persisted as one of the defining aspects of naval warfare. The chapter deals with the specificity of waging war at sea and related legal issues. It draws both from state-military practice and from the specialised legal literature that started to appear at the time. Subjects which are covered include the main rules of naval warfare, privateering, the treatment of prisoners of war, the bombardment of coastal cities, prize law and the role of admiralty courts. Particular attention is devoted to the issue of maritime neutrality. Indeed, the recurrent tension between the respective rights and duties of neutrals and belligerents assumed great relevance in this period, being often dealt with in international treaties and legal scholars’ treatises.

Between 1660 and 1775 the number of European countries with diplomatic relations with the Ottoman Empire that obtained ahdames of their own grew rapidly, but many of these newcomers did not establish networks of consulates and vice-consulates in the eastern Mediterranean. Instead, they appointed the consuls of other European nations as their vice-consuls. This did not hurt the legal privileges of the merchants from these countries. In the course of the seventeenth and eighteenth centuries, some nations asked the Ottoman government to renew their capitulations several times with the single aim of obtaining more privileges. This development culminated in the French capitulations of 1740, which incorporated the clauses of virtually all earlier ahdnames. In the eyes of many Ottomans, the capitulations of 1740 came to symbolise the Europeans’ ceaseless attempts to obtain more and more privileges from the Turks. But the French renewal of their capitulations in 1673 already laid the foundations for the rise of imperialism. It was then that the Ottoman authorities granted Ottoman subjects working for foreigners as interpreters or as warehousemen the same fiscal and legal status as the Westerners. It was also in 1673 that the French had their role as protectors of the Christian Holy Places in Jerusalem, as well as of all Catholic clergymen – not just Western missionaries, but all Catholic clerics – in the Levant codified in their capitulations. It was this French model that the Russians used in 1774 to claim their own protectorate over all Greek Orthodox Christians in the Ottoman realm.

By the middle of the seventeenth century, a category of sovereign princes and polities had succeeded in monopolising jurisdiction over external relations and the internal machinery of government that allows to speak of sovereign state. The Old Regime saw the further emergence, in governmental and diplomatic practice as well as in learned writings of the paradigm of the law of nations as the preserve of sovereigns. As legal practice and literature, it also expanded in scope and mass to new regulatory fields such as the law of the sea, maritime warfare, neutrality or dispute settlement. The great treatises on the law of nations of the middle of the eighteenth century fleshed out the dualist system of law of nature and of nations that formed one of the intellectual backbones to Grotius’ work into an elaborate framework of the governance of international relations inside Christian Europe and for its imperial expansion outside.