From the end of the seventeenth century the idea of Europe took on a more concrete form as a result of the crystallization of new political structures and geopolitical frameworks in the wake of the Thirty Years War, 1618–1648. The post-1648 Westphalian political order that ushered in the age of sovereign states saw the end of the era of the wars over religion and schisms that followed. The early modern period was an era of wars over religion and related dynastic struggles, at least since 1713 with the Peace of Utrecht that saw the end of the War of the Spanish Succession. The emergence of the idea of Europe can be seen in the context of what Rabb (1975) has called the 'struggle for stability" in the seventeenth century. The eighteenth century, in contrast, was one of relative stability and consolidation for the post-1648 order. In this period new political ideas emerged in response to the crisis of the wars of religion and the recognition that the unity of Europe cannot be a political unity- One concrete outcome was the rise of the nation-state and the European inter-state system which shaped world politics for the next three centuries (Tilly 1990). The Reformation had led to a major division between the Catholic south and the Protestant north, and as discussed in the previous chapters, a division had also taken root between the sea-based empires of the West and the land-based ones of Central Europe.