The Battle of Monte Cassino was a major battle fought on the Italian front of World War II from 17 January to 18 May 1944.
At the start of 1944, the Allied armies of Britain and United States advanced up the "boot" of Italy with the objective of liberating Rome from Nazi Germany's occupation. They soon came up against the Wehrmacht's "Winter Line" and the "Gustav Line", anchored at Monte Cassino to the south of Rome. On 17 January 1944, the British X Corps launched the first Allied attack on Monte Cassino, but the German 94th Infantry Division was reinforced by the 29th Panzergrenadier Division and the 90th Panzergrenadier Division, and the British suffered 4,000 losses. On 20 January, the US 36th Infantry Division launched a costly attack on the German line, resulting in 2,100 American losses. Due to the failures of several previous ground attacks, the Allies marked the abbey of Monte Cassino for destruction, and, on 15 February, American bombers dropped 1,400 tons of high explosives, causing widespread damage; however, German fallschirmjaegers occupied the rubble and established excellent defensive positions among the ruins. On 16 May 1944, an assault by the Polish II Corps, spearheading an assault of 20 divisions, led to the Polish flag and the British Union Jack being raised over Monte Cassino on 18 May. The capture of Monte Cassino led to the collapse of the Senger Line on 25 May, and Rome was liberated by Mark W. Clark's American forces on 4 June 1944. The capture of Monte Cassino cost the Allies 55,000 men, while the Germans suffered only 20,000 losses.