The Army was reorganized, and a portion placed under the command of André Masséna and merged with the Army of Helvetia. Following the reorganization and change in command, the Army participated in several skirmishes and actions on the eastern part of the Swiss Plateau, including the Battle of Winterthur. After this action, three forces of the imperial army united north of Zürich, completing a partial encirclement of Masséna's combined Army of the Danube and Army of Switzerland. A few days later, at the First Battle of Zurich, Masséna was forced west, across the Limmat. In late summer, 1799, Charles was ordered to support imperial activities in the middle Rhineland; he withdrew north across the Rhine, and marched toward Mannheim, leaving Zürich and northern Switzerland in the hands of the inexperienced Alexander Korsakov and 25,000 Russian troops. Although the highly capable Friedrich Freiherr von Hotze remained in support, his 15,000 men were not able to counter Korsakov's poor defensive arrangements. Three weeks later, at the Second Battle of Zurich, the Russian force was annihilated, and Hotze was killed south of Zürich. This left Masséna in control of northern Switzerland, and closed forced Suvorov into an arduous three-week march into the Vorarlberg, where his troops arrived, starving and exhausted, in mid-October.