Peace of Westphalia Signed

Setting the scene

The Thirty Years' War (1618-1648) devastated Central Europe, killing 8 million people through battle, famine, and disease—20% of Germany's population. It began as a religious conflict between Catholics and Protestants in the Holy Roman Empire but became a continental struggle involving Spain, France, Sweden, and the Dutch. Armies lived off the land, destroying crops and spreading plague. The war featured atrocities like the Sack of Magdeburg in 1631, where 20,000 civilians were killed. By 1648, all sides were exhausted and bankrupt.

What happened

Peace negotiations began in 1644 in the Westphalian cities of Münster and Osnabrück, involving 109 delegations. The treaties were signed on October 24, 1648. The Peace of Westphalia recognized the sovereignty of over 300 German princes, allowing them to choose their state's religion (Catholicism, Lutheranism, or Calvinism). It granted independence to the Dutch Republic and Switzerland, and awarded territory to France and Sweden. Critically, it established the principle of cuius regio, eius religio (whose realm, his religion) and non-interference in domestic affairs.

Why it still matters

Westphalia created the modern system of sovereign nation-states, ending the medieval idea of a unified Christendom under pope and emperor. It established the principle of Westphalian sovereignty—states have exclusive authority within their borders—that remains the foundation of international law. The treaty also marked the decline of the Holy Roman Empire and the rise of France as Europe's dominant power. The negotiations pioneered modern diplomacy with multilateral talks and permanent embassies. The 'Westphalian system' governed international relations for 350 years until challenged by globalization and humanitarian intervention in the 1990s.

Background

It is often linked to the rise of modern state sovereignty. Even centuries later, this episode remains a reference point for how empires rise, fracture, and transform.