A fresh army was collected under Field Marshal Khevenhüller at Vienna, and the Austrians planned an offensive winter campaign against the Franco-Bavarian forces in Bohemia and the small Bavarian army that remained on the Danube to defend the electorate. The French in the meantime had stormed Prague on the 26th of November, the grand-duke Francis, consort of Maria Theresa, who commanded the Austrians in Bohemia, moving too slowly to save the fortress. The elector of Bavaria, who now styled himself archduke of Austria, was crowned king of Bohemia (19th December 1741) and elected to the imperial throne as Charles VII. (24th January 1742), but no active measures were undertaken. In Bohemia the month of December was occupied in mere skirmishes. On the Danube, Khevenhüller, the best general in the Austrian service, advanced on the 27th of December, swiftly drove back the allies, shut them up in Linz, and pressed on into Bavaria. Munich itself surrendered to the Austrians on the coronation day of Charles VII. At the close of this first act of the campaign the French, under the old Marshal de Broglie, maintained a precarious foothold in central Bohemia, menaced by the main army of the Austrians, and Khevenhüller was ranging unopposed in Bavaria, while Frederick, in pursuance of his secret obligations, lay inactive in Silesia. In Italy the allied Neapolitans and Spaniards had advanced towards Modena, the duke of which state had allied himself with them, but the vigilant Austrian commander Count Traun had outmarched them, captured Modena, and forced the duke to make a separate peace.
4. Campaign of 1742. - Frederick had hoped by the truce to secure Silesia, for which alone he was fighting. But with the successes of Khevenhüller and the enthusiastic "insurrection" of Hungary, Maria Theresa's opposition became firmer, and she divulged the provisions of the truce, in order to compromise Frederick with his allies. The war recommenced. Frederick had not rested on his laurels; in the uneventful summer campaign of 1741 he had found time to begin that reorganization of his cavalry which was before long to make it even more efficient than his infantry. Charles VII., whose territories were overrun by the Austrians, asked him to create a diversion by invading Moravia. In December 1741, therefore, Schwerin had crossed the border and captured Olmütz. Glatz also was invested, and the Prussian army was concentrated about Olmütz in January 1742. A combined plan of operations was made by the French, Saxons and Prussians for the rescue of Linz. But Linz soon fell; Broglie on the Moldau, weakened by the departure of the Bavarians to oppose Khevenhüller, and of the Saxons to join forces with Frederick, was in no condition to take the offensive, and large forces under Prince Charles of Lorraine lay in his front from Budweis to Iglau. Frederick's march was made towards Iglau in the first place.
Brünn was invested about the same time (February), but the direction of the march was changed, and instead of moving against Prince Charles, Frederick pushed on southwards by Znaim and Nikolsburg. The extreme outposts of the Prussians appeared before Vienna. But Frederick's advance was a mere foray, and Prince Charles, leaving a screen of troops in front of Broglie, marched to cut off the Prussians from Silesia, while the Hungarian levies poured into Upper Silesia by the Jablunka Pass. The Saxons, discontented and demoralized, soon marched off to their own country, and Frederick with his Prussians fell back by Zwittau and Leutomischl to Kuttenberg in Bohemia, where he was in touch with Broglie on the one hand and (Glatz having now surrendered) with Silesia on the other. No defence of Olmütz was attempted, and the small Prussian corps remaining in Moravia fell back towards Upper Silesia. Prince Charles, in pursuit of the king marched by Iglau and Teutsch (Deutsch) Brod on Kuttenberg, and on the 17th of May was fought the battle of Chotusitz or Czaslau, in which after a severe struggle the king was victorious.
His cavalry on this occasion retrieved its previous failure, and its conduct gave an earnest of its future glory not only by its charges on the battlefield, but its vigorous pursuit of the defeated Austrians. Almost at the same time Broglie fell upon a part of the Austrians left on the Moldau and won a small, but morally and politically important, success in the action of Sahay, near Budweis (May 24, 1742). Frederick did not propose another combined movement. His victory and that of Broglie disposed Maria Theresa to cede Silesia in order to make good her position elsewhere, and the separate peace between Prussia and Austria, signed at Breslau on the 11th of June, closed the First Silesian War. The War of the Austrian Succession continued.
5. The French at Prague. - The return of Prince Charles, released by the peace of Breslau, put an end to Broglie's offensive. The prince pushed back the French posts everywhere, and his army converged upon Prague, where, towards the end of June 1742, the French were to all intents and purposes surrounded. Broglie had made the best resistance possible with his inferior forces, and still displayed great activity, but his position was one of great peril. The French government realized at last that it had given its general inadequate forces. The French army on the lower Rhine, hitherto in observation of Hanover and other possibly hostile states, was hurried into Franconia. Prince Charles at once raised the siege of Prague (September 14), called up Khevenhüller with the greater part of the Austrian army on the Danube, and marched towards Amberg to meet the new opponent. Marshal Maillebois (1682-1762), its commander, then manoeuvred from Amberg towards the Eger valley, to gain touch with Broglie. Marshal Belleisle, the political head of French affairs in Germany and a very capable general, had accompanied Broglie throughout, and it seems that Belleisle and Broglie believed that Maillebois' mission was to regain a permanent foothold for the army in Bohemia; Maillebois, on the contrary, conceived that his work was simply to disengage the army of Broglie from its dangerous position, and to cover its retreat.