On September 9, 1943, the Fifth Army, composed of the U.S. VI Corps, under Major General Ernest J. Dawley—who was a decade older than Clark and about whom Clark had doubts—and the British X Corps, under Lieutenant General Sir Richard L. McCreery—to whom Clark would later scornfully refer as a "feather duster"—under Clark's command landed at Salerno (codenamed Operation Avalanche). The invasion, despite good initial progress, was nearly defeated over the next few days by numerous German counterattacks and Major General Dawley, the VI Corps commander, was sacked and replaced by Major General John P. Lucas, who himself was later sacked and replaced after his perceived failure during Operation Shingle. Clark was subsequently criticized by historians and critics for this near-failure, blamed on poor planning by Clark and his staff. Despite this, however, Clark was later awarded the Distinguished Service Cross. The Fifth Army, by now composed of five American divisions (the 3rd, 34th, 36th and 45th Infantry, along with the 82nd Airborne) and three British divisions (7th Armoured, 46th and 56th Infantry), operating alongside the British Eighth Army, under General Bernard Montgomery, subsequently advanced up the spine of Italy, and captured the Italian city of Naples on October 1, 1943 and crossed the Volturno Line in mid-October. Progress, however, soon began to slow down, due to German resistance, lack of Allied manpower in Italy, and the formidable German defenses known as the Winter Line, which was to hold the Allies up for the next six months.