In March, Masséna's army occupied Switzerland, preparing an attack against Tyrol through Vorarlberg. However, the defeats of French armies in Germany and Italy forced him to return to the defensive. Taking over Jourdan's army, he pulled it back into Switzerland to Zürich. Archduke Charles pursued him and drove him back west at the First Battle of Zurich. The French general André Masséna was forced to yield the city to the Austrians under Archduke Charles and retreat beyond the Limmat, where he managed to fortify his positions, resulting in a stalemate. During the summer, Russian troops under general Korsakov replaced the Austrian troops.