The Thirty Years' War

The Winter King is broken at White Mountain

On 8 November, outside Prague, the Catholic League army under Tilly and the imperial forces crush the Bohemian rebels at the Battle of White Mountain in barely an hour. Frederick V flees into exile; his reign has lasted one winter. The Bohemian nobility is executed or dispossessed, the kingdom forcibly re-Catholicised, and the Habsburg grip on central Europe restored.

Denmark enters — and Tilly wins at Lutter

Alarmed by the Catholic advance into northern Germany, King Christian IV of Denmark intervenes as champion of the Protestant cause. On 27 August at Lutter, Tilly routs the Danish army. Meanwhile the emperor's new generalissimo, the Bohemian entrepreneur Albrecht von Wallenstein, raises a vast private army and sweeps the Protestants from the north. By 1629 the imperial cause is triumphant from the Alps to the Baltic.

Ferdinand overreaches

On 6 March, at the height of his power, Emperor Ferdinand II issues the Edict of Restitution, ordering the return to the Catholic Church of all ecclesiastical lands secularised since 1552. The edict alarms Lutheran and Catholic princes alike, who fear an imperial absolutism that would crush the liberties of the German states. Ferdinand's triumph sows the seeds of his undoing.

Magdeburg burns

On 20 May, after a long siege, Tilly's imperial and Leaguer army storms the Protestant city of Magdeburg. In the sack that follows, fire consumes the city and some 20,000 of its 25,000 inhabitants perish. The atrocity horrifies Protestant Europe and becomes a byword for the war's savagery; 'Magdeburg quarter' enters the language as a synonym for no mercy at all.

Gustavus Adolphus triumphs at Breitenfeld

King Gustavus Adolphus of Sweden — the 'Lion of the North' — has landed in Pomerania in 1630 with a disciplined, professional army and revolutionary tactics of mobile artillery and combined arms. On 17 September at Breitenfeld, near Leipzig, he annihilates Tilly's hitherto invincible army. It is the first great Protestant victory of the war, and it carries the Swedes deep into Catholic Germany.

Breitenfeld is often called the birth of modern warfare. Gustavus's lighter, more mobile formations, his massed field guns, and his integration of infantry, cavalry, and artillery broke the ponderous Spanish-style squares that had dominated the battlefield for a century. For a year the Swedish king marched almost at will through Germany. His subsidies came from Catholic France: Cardinal Richelieu, pursuing raison d'état, funded the Protestant champion against the Habsburgs.

The Lion falls

On 16 November, in fog near Lützen, the Swedes under Gustavus Adolphus meet Wallenstein, recalled to imperial command. The Swedes win the field, but the king, leading a cavalry charge, is shot from his horse and killed. The Protestant cause loses its inspired leader; the war, deprived of its one figure who might have ended it in victory, grinds on without direction.

Richelieu declares war on Spain

After the Swedes are crushed at Nördlingen in September 1634 and the German Protestants make the Peace of Prague with the emperor, France abandons its role as paymaster and enters the war openly. On 19 May 1635 Louis XIII declares war on Habsburg Spain. What had been a German religious war becomes a continental struggle for power between the Bourbons and the Habsburgs, fought from the Rhine to the Pyrenees.

The Spanish tercios break at Rocroi

On 19 May, five days after the death of Louis XIII, the twenty-one-year-old Duke of Enghien — the future Great Condé — destroys the army of Spain at Rocroi in the Ardennes. The famous Spanish tercios, the finest infantry in Europe for a century, stand and die where they fought. The battle shatters the myth of Spanish invincibility and announces the rise of France as the first military power on the continent.

Westphalia and the birth of the modern state system

On 24 October, after five years of negotiation at Münster and Osnabrück, the Peace of Westphalia ends the war. Calvinism is recognised; the German princes win near-sovereignty; the Dutch and the Swiss gain independence; France and Sweden take territory and prestige. The dream of a universal Catholic empire is dead. In its place stands a Europe of sovereign states, each supreme within its borders.

The war had killed perhaps eight million people — as much as a third of the population of Germany in the worst-hit regions — through battle, famine, and plague. Whole provinces were depopulated and would not recover for generations. But the settlement of 1648 founded the principle of state sovereignty and non-interference that historians call the 'Westphalian system' — the constitutional grammar of international relations down to the present day.