In 1636 France was invaded. The Cardinal-Infant crossed the Somme, took Corbie, and advanced to the banks of the Oise. All Paris was in commotion. An immediate siege was expected, and inquiry was anxiously made into the state of the defences. Then Richelieu, coming out of his seclusion, threw himself upon the nation. He appealed to the great legal, ecclesiastical, and commercial corporations of Paris, and he did not appeal in vain. Money, voluntarily offered, came pouring into the treasury for the payment of the troops. Those who had no money gave themselves eagerly for military service. It was remarked that Paris, so fanatically Catholic in the days of St. Bartholomew and the League, entrusted its defence to the Protestant marshal La Force, whose reputation for integrity inspired universal confidence. [Sidenote: § 3. The invaders driven back.] The resistance undertaken in such a spirit in Paris was imitated by the other towns of the kingdom. Even the nobility, jealous as they were of the Cardinal, forgot their grievances as an aristocracy in their duties as Frenchmen. Their devotion was not put to the test of action. The invaders, frightened at the unanimity opposed to them, hesitated and turned back. In September, Lewis took the field in person. In November he appeared before Corbie; and the last days of the year saw the fortress again in the keeping of a French garrison. The war, which was devastating Germany, was averted from France by the union produced by the mild tolerance of Richelieu. [Sidenote: § 4. Battle of Wittstock.] In Germany, too, affairs had taken a turn. The Elector of Saxony had hoped to drive the Swedes across the sea; but a victory gained on October 4, at Wittstock, by the Swedish general, Baner, the ablest of the successors of Gustavus, frustrated his intentions. Henceforward North Germany was delivered over to a desolation with which even the misery inflicted by Wallenstein affords no parallel. [Sidenote: § 5. Death of Ferdinand II.] Amidst these scenes of failure and misfortune the man whose policy had been mainly responsible for the miseries of his country closed his eyes for ever. On February 15, 1637, Ferdinand II. died at Vienna. Shortly before his death the King of Hungary had been elected King of the Romans, and he now, by his father's death, became the Emperor Ferdinand III. [Sidenote: § 6. Ferdinand III.]