Thirty Years' War

The Thirty Years' War was caused by political and religious problems, much like any other conflicts during this time. There were strong tensions between Catholic and Protestant states that caused initial conflict, however a revolt against Habsburg rule in 1618 started the actual warefare. This caused a widespread war across Europe involving more countries such as Spain and the Netherlands who previously had a truce between them, which expired in 1621. After the war was over, it had caused much economic devestation and also a very large population decline. A series of treaties called the Peace of Westphalia in 1648 eventually ended the fighting in the empire for good.