A revolt in Bohemia in 1618 ignited the religious tensions suppressed in Germany by the Peace of Augsburg. Augsburg allowed German princes to choose between Lutheranism and Catholicism but made no provision for Calvinism. Adding to the tensions was the power of the Hapsburgs who ruled Austria, Bohemia and Hungary with their Spanish branch controlling Spain, Portugal, Italy and the Netherlands. Once ignited the failure of the Hapsburgs to avoid overreach in victory and the alarm of their enemies at the expansion of Hapsburg power turned the conflict into a European conflagration.
The Hapsburgs crushed the Bohemian revolt with ease but triggered alarm by stripping the Elector Frederick V of the Palatinate of his possessions and Electoral dignity. Spain saw an opportunity to crush the Dutch Revolt ending the uneasy truce with the United Provinces. Rising Protestant alarm brought Christian IV of Denmark into the anti-Hapsburg coalition. When he was beaten Emperor Ferdinand II overreached by issuing the Edict of Restitution. This was a retroactive move to restore Catholic lands lost since Augsburg allowed forcible Protestant reconversion in violation of Augsburg. It alienated Protestant states like Saxony that until now had supported or not actively opposed the Emperor.
This brought Gustav II on Sweden into the conflict in 1630 and for the first time the Hapsburgs cause suffered military defeats on the field. Even though Gustav was killed in his victory at the Battle of Lützen, the Swedes remained in the field. A broken Ferdinand II signed the Peace of Prague in 1635 essentially revoking the Edict of Restitution and granting amnesty to the German princes other than the heirs of Elector Frederick V.
This could have ended the war but it did not satisfy Sweden or Spain (the Dutch had still not been subdued). The prospect of strengthened Hapsburg might from the Peace frightened France (which even though Catholic had been subsidizing the Protestants) and resulted in Catholic France joining the Protestant German states against the Catholic Hapsburgs. And so the war dragged on. By 1648 most of the monarchs at the commencement of the conflict Philip III of Spain, Emperor Ferdinand II, Maurice of Orange Stadholder of the Netherlands, Elector Frederick V, Louis XIII of France and Cardinal Richelieu were dead as the exhausted combatants battled on. Negotiations between the Emperor, France and Sweden had commenced in 1644 at Osnabrück and Münster in Westphalia.
The final end to the war would not come from one treaty, but a series of treaties. On May 15, 1648 the Peace of Münster between Spain and the United Provinces marked the end of the Dutch Revolt and recognized the independence of the Netherlands. This marked the first step of the Westaphalian Peace – with complementary treaties signed on October 24 at Münster between the Emperor, France and Osnabrück between the Emperor, Sweden and their allies finally signed ending the war in Germany.
Key provisions of Westphalia included:
- A restoration of a reduced Rhenish Palatinate to the eldest son of the Elector Frederick V who was also raised to Elector.
- Augsburg was reaffirmed and now Calvinism was an acceptable religious option.
- Christian denominations living in principalities where they were not the established denomination were given some freedom of religion.
- Switzerland achieved its independence from the Holy Roman Empire.
- Of greatest import to inter-state relations it established the concept of Westphalian sovereignty and the principle of non-intervention in the affairs of another state.
Westphalia did not bring peace to Europe. France and Spain remained at war. Both were exhausted and France was about to enter into the domestic turmoil of the Fronde memorialized in Dumas second Musketeer novel – Twenty Years After. That war would continue for another 11 years until the Treaty of the Pyrenees marked the defeat of Spain and its fall from the rank of the Great Powers.