The immense difficulties Sicily's rugged terrain caused to the Allied forces, and the successful delaying actions fought by small numbers of well-led German soldiers, inspired Hitler and his generals to garrison Italy as an obstacle to British and American advance. A relatively limited number of Wehrmacht troops used the endless series of mountain ridges and defensible hilltop towns to slow the offensive to a crawl, tying down large numbers of Western troops.

Under Albert Kesselring's expert leadership, the Germans fell back northward methodically, fighting a major delaying action at Volturno in mid-October 1943. The Wehrmacht then established themselves on the Reinhard Line, a temporary defensive front meant to delay the Allies until the Germans finished preparing the stronger Gustav Line, stretching from Gaeta to Ortona and anchored on the formidable strongpoint near the early medieval monastery of Monte Cassino.

The Allies did not intend the attack on Cassino as a simple slogging match, understanding quite clearly the cost of such an operation. Instead, they planned a landing at Anzio by an entire army corps, the U.S. 6th Corps, to outflank the Gustav Line and force the Germans' withdrawal to avoid encirclement. It was a sound plan, but it would turn into something of a fiasco under the leadership of Major General John P. Lucas. The Anzio landing occurred on schedule on January 22, 1944, and despite achieving total tactical surprise, Lucas squandered the opportunity to run amok in the Gustav Line's rear by remaining supinely in Anzio. Winston Churchill, with his typical verve, excoriated Lucas' failure with a colorful description: "Instead of hurling a wildcat onto the shore all we got was a stranded whale." A later German report also expressed surprise at Lucas' inaction.

What followed was months of bitter fighting as the Allies struggled to break out of their beachhead and make their long-awaited push to Rome.