 As the rest of the XIX Corps flowed into the wake of this spectacular drive, the 1st Army was completing its equally remarkable thrust around the southern and eastern edges of the Ruhr.The 1st Army's drive from the Remagen bridgehead began with a breakout before dawn on 25 March.German Field Marshal Walter Model, whose "Army Group B" was charged with the defense of the Ruhr, had deployed his troops heavily along the east–west Sieg River south of Cologne, thinking that the Americans would attack directly north from the Remagen bridgehead.