 Complete the following phrase:  Walker commanded the 36th Division during the whole of its service in the grueling slog up Italy, crossing the Volturno Line in October, and by late Novemberearly December, by which time the division was part of Major General Geoffrey Keyes U.S. II Corps, were fighting in front of the Bernhardt Line, part of the formidable Winter Line defenses, suffering heavy casualties in the Battle of San Pietro Infine, later participating in the Rapido river crossing, part of the 