Germany's North African defeat opened up the possibility of taking the war in the West to the European continent for the first time since France's lightning conquest by the Wehrmacht in 1940. The British and Americans debated the merits of landing in France directly in 1943, but they ultimately opted against it. The Soviets railed at the Westerners as “bastards of allies” - conveniently forgetting that they aided and abetted Hitler's violent expansionism in Eastern Europe for over a year, starting in 1939 - but a 1943 “D-Day”-style landing in France might have proven a strategic and logistical impossibility. 

Complex reasons lay behind England's successful insistence on the Mediterranean theater rather than the French theater as the scene of the next Western Allied strike against Nazi Germany. Chief among these remained Britain's determination to keep a postwar empire, one that Churchill and his cabinet hoped would include Iraq and Iran, the source of oil needed to ensure that England continued to “rule the waves” with a powerful modern navy. This strategic imperative, indeed, formed the backbone of the British choice of Sicily as the target for military operations in the summer of 1943.

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 and frequently inflicting heavy casualties.

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.

In broad outlines, the Allied strategy witnessed the British 8th Army under the tenacious but extremely undiplomatic Bernard Montgomery advancing up the eastern, or Adriatic, side of the Italian Peninsula. The United States Fifth Army, meanwhile, pushed up the western side of Italy flanked by the Tyrrhenian Sea, directly towards the key town of 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 US 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: “The Allies on the beachhead on the first day of the landing did not conform to the German High Command's expectations. Instead of moving northward with the first wave to seize the Alban Mountains...the landing forces limited their objective. Their initial action was to occupy a small beachhead".