As winter broke in 1799, on 1 March, General Jean-Baptiste Jourdan and his army of 25,000, the Army of the Danube, crossed the Rhine at Kehl. Instructed to block the Austrians from access to the Swiss alpine passes, Jourdan planned to isolate the armies of the Coalition in Germany from allies in northern Italy, and prevent them from assisting one another. By crossing the Rhine in early March, Jourdan acted before Charles' army could be reinforced by Austria's Russian allies, who had agreed to send 60,000 seasoned soldiers and their more-seasoned commander, Generalissimo Alexander Suvorov. Furthermore, if the French held the interior passes in Switzerland, they could prevent the Austrians from transferring troops between northern Italy and southwestern Germany, and use the routes to move their own forces between the two theaters.