In Operation Plunder, starting on 13 March 1945, the British Second Army and the US Ninth Army crossed the Rhine at various places north of the Ruhr and German resistance in the west quickly crumbled. The First Canadian Army wheeled left and liberated the northern part of the Netherlands and captured adjoining areas of Germany, the British Second Army occupied much of north-west Germany and the US Ninth Army formed the northern arm of the envelopment of German forces in the Ruhr Pocket and on 4 April reverted to Omar Bradley's 12th Army Group.