The Thirty Years War begun with the Czech rebellion against oppression of Austria ruled by Habsburgers. The Catholic League, a military alliance formed in 1609, advanced against Czechs. The League comprised German Catholic principalities, Austria, and Spain; also the Emperor supported it. At the war beginning Czechs gained several victories and even took Vienna suburbs by assault. However, the Catholic League has managed to regroup forces and deliver a crushing blow to the enemy. In 1620 Czech Army was smashed in the battle of the White Mountain. All these events gave the Protestant Europe a signal to interfere with the war. In 1625, England, Holland, and Denmark put up resistance to Catholics. France, the old opponent and rival of Habsburger dynasty (that ruled Austria and Spain), abundantly financed the Protestant forces. War enveloped the most of Europe. Catholics crushed Danish forces. England and Holland could not hold back the Catholic union, because their armies were too small and poorly organized. A real peril of enemy invasion threatened France. Cunning politician Cardinal Richelieu has managed to ward off this disaster from his country. He entered into an alliance with the Swedish King Gustaf Adolf. Richelieu undertook paying off one million livres annually for "resurrection of free Germany". In 1630 the Gustaf Adolf's army initiated a full-scale offensive. In early 1631 they took the whole Pommern. In September of the same year Swedes gained a glorious victory in the battle of Leipzig (Breitenfeld), and the whole Northern Germany was in their hands. In November of 1632, Swedish army crushed forces of the Catholic League in the battle of Lutzen. However, it was a Pyrrhic victory. The talented leader and military reformer, the Swedish King and military commander Gustaf Adolf has perished in this battle. Swedish forces were disorganized. In August of 1634 Swedish army was defeated in the battle of Nordlingen. Under these circumstances, France had no choice but to levy war on Austria. Holland, Mantua, Savoie, and Venice supported France. At first, Frenchmen were forced to defend their lands from invasion, but gradually French army grew stronger, and the battleground shifted to the enemy territories. In May of 1643 Frenchmen crushed the Spanish Army in the battle of Rocroi, and in 1648 the war finished with a general debacle of Austria and its allies.