30 Years War



The 30 Years' War was the the last major war of the Protestant Reformation. This war began in the Holy Roman Empire but specifically in Bohemia(modern day Czech Republic). The war had four phases, the Bohemian and Danish phases which were local and religious, and the Swedish and French phases which were more political and continental. The war was caused when Catholic ruler Ferdinand Archduke of Styria, who ruled mostly protestant Bohemia, revoked the the Letter of Majesty that allowed protestant toleration. In anger, the protestants rebelled. This led to the Defenestration of Prague which was when the protestants threw Ferdinand's messengers out of a 70 ft high window. Ferdinand wanted to get the protestants in line and began an internal war. In the Danish phase the Lutheran King Christian lV of Denmark got involved but got quickly defeated by an ally of Ferdinand's, Maximilian of Bavaria. Then, the Swedish phase turned the war in the protestants favor when Sweden became directly involved. Gustavus Adolphus ll, Lutheran King of Sweden, was funded by France and led the victory . Lastly the French phase, which was the longest and most political phase, began when Gustavus Adolphus died in battle. The French then had to enter the fight. The French fought more for the balance of power than religion. By 1648 people began to get tired and signed the The Treaty of Westphalia which weakened the the Holy Roman Emperor and shifted political powers.

What started the War

The cause of this war was the revoking of the Letter of Majesty by Ferdinand ll. The Letter of Majesty was broadened by Emperor Rudolf ll and granted protestants toleration in Bohemia. This allowed the larger population of protestants to practice their religion despite the fact that they had a Catholic ruler and The Peace of Augsburg which was established the rule that the one who rules establishes the religion except for Calvinism. This then led to a continental feud between Protestants and Catholics.

Key Figures/Groups

  • Protestants- Religion started during the Renaissance by Martin Luther
  • Catholics- Religion of the Holy Roman Empire and the church had had power over everything before the Reformation
  • Danish-Tried to help the protestants but were defeated, causing Sweden to step in
  • French- Catholic country that supported Sweden’s fight for the protestants because of political reasons
  • Gustavus Adolphus- King of Sweden, Father of Modern Warfare, was the turning point of the war when he won a battle between the protestants and the Catholics.
  • Ferdinand II- King of Bohemia for a time, he started the battle in Bohemia when he took power and revoked the Letter of Majesty


There was no clear winner in the 30 Years' War. It was eventually stopped because people had gotten so tired of fighting. They signed the Treaty of Westphalia and Ferdinand's Edict of Restitution reasserted the religious settlement of the Peace of Augsburg.

Main Significance

The result of the war caused an increase in countries having more control over themselves in Holy Roman Empire, limiting the power of the Emperor and decentralizing authority in German-speaking central Europe. It was also the last religious war in Europe and basically wrapped up the whole Protestant Reformation. Which then led to the distinctive-nation states to reach maturity and firmly establish the competitive nationalism of the modern word.

Primary Source


The Peace of Augsburg was written to try to settle the religious conflict between protestants and Catholics. I basically states that the ruler of the lands religion becomes the official religion. If the subjects did not like it they could move to a new land. But it only recognized Lutherans and Catholics.