HISTORICAL FOUNDATIONS OF THE INTERNATIONAL POLITICAL SYSTEM

2.1. Historical Background: Europe before Westphalia

The early seventeenth century was a period of profound instability in Europe. The Protestant Reformation, initiated by Martin Luther in 1517, had fractured the unity of Western Christendom, giving rise to fierce religious, political, and territorial conflicts. The Holy Roman Empire, a loose confederation of over three hundred semi-autonomous states, became the epicenter of these struggles. Within this context, the Thirty Years’ War began not as a continental conflict but as a localized religious dispute within the Empire.

The Outbreak of the Thirty Years’ War (1618–1625)

The war’s immediate cause was the Defenestration of Prague in 1618, when Protestant nobles in Bohemia rebelled against Emperor Ferdinand II’s attempts to reimpose Catholic dominance. The revolt symbolized the broader struggle between Protestant and Catholic powers, as well as between central authority and regional autonomy. The conflict quickly escalated when Ferdinand, supported by the Catholic League and Spain, sought to crush the rebellion, while Protestant princes looked to foreign allies such as Denmark, Sweden, and France for support.

The early phase of the war, known as the Bohemian and Danish phases, saw Catholic victories under the leadership of generals like Johann Tilly and Albrecht von Wallenstein. Protestant forces were severely weakened, and the imperial cause appeared dominant. However, the intervention of foreign powers soon transformed the conflict into a European-wide war.

The Internationalization of the Conflict (1625–1648)

In 1630, Gustavus Adolphus of Sweden entered the war, motivated by both religious and strategic concerns. His campaigns revitalized the Protestant cause, achieving significant victories before his death at the Battle of Lützen in 1632. Following his death, Sweden remained active under Chancellor Axel Oxenstierna, supported financially by France—a Catholic power that paradoxically aligned with Protestant states to counterbalance Habsburg influence.

The entry of France in 1635 against Spain and the Holy Roman Empire marked the final, most destructive phase of the war. By this point, religious motivations had largely given way to political ambitions. The conflict evolved into a struggle for the European balance of power, with France and Sweden seeking to curtail Habsburg dominance in both Central Europe and the Low Countries.

The war devastated the German lands, causing immense human and economic loss. Historians estimate that some regions of the Empire lost up to one-third of their population. Entire cities were ruined, agriculture collapsed, and famine and disease spread widely. By the 1640s, all belligerents recognized the necessity of peace, not only to end the suffering but also to restore political stability.