When the corps broke out during Operation Diadem, it was ordered by the Fifth Army commander, Lieutenant General Mark Clark north west up the coast towards Rome instead of advancing northeast to block the German line of retreat from Cassino on the Gustav Line, leading to prolonged and bloody combat before it was taken by a combination of American, British, Canadian, French, and Polish troops. By disobeying his orders Clark received the glory of capturing the vacant Italian capital–abandoned without resistance by the Germans and left an open city–but was castigated by his peers and superiors for failing to trap and destroy the German forces. This, along with the poor performance at Anzio, would cast a shadow over the reputation of the corps.