Like the great wars of the sixteenth century, the Thirty Years’ War of 1618-1648 was in part a conflict over religions. This time, however, most of the fighting took place in Germany. The Habsburg emperor, Ferdinand II (r. 1619-1637), made the last serious political and military effort to unify Germany under Catholic rule.
The Thirty Years’ War began as a conflict between Catholics and Protestants; it ended as a struggle to reduce the power of the Habsburgs. The war finally involved most of the European powers and their colonies. It was, in the context of the times, the first “world war.”