In 1940, Italy declared war on the British Empire. Now the Italians had joined the war, the Mediterranean and North Africa became a notable front for both sides. As Italy invaded Egypt, Britain's Suez Canal became a target for the Axis.

However, Italy's advance into Egypt did not last long; and soon the British had pushed the Italians back into Libya. During Operation Compass Italy's armies retreated further into Libya, and hundreds of thousands of its troops surrendered. With this defeat the Italians could potentially be pushed out of North Africa.

Further defeats followed at sea. At the Battle of Taranto the Royal Navy targeted the Italian fleet in port with aircraft carriers. Three Italian battleships were lost during the airstrike. Britain had gained the advantage in North Africa and Mediterranean.

The Italians called upon their German allies for assistance. Given the strategic value of Suez, which would provide a pathway to Allied oil supplies, the Nazis sent a number of divisions to re-enforce the Italians. The German and Italians combined their armies into one, the Afrika Korps, under the leadership of Rommel.

The Afrika Korps began to turn the tide against the U.K. during 1941. Germany and Italy pushed Britain out of Libya and back into Egypt. Although pockets of the British army held firm at Tobruk, and Rommel could not take the city. Britain lifted the siege with Operation Crusader.

In 1942, Britain defeated the Afrika Korps at the Battle of El Alamein. With that victory the Allies were now clearly winning the war in North Africa. The British were soon re-enforced with American troops in late 1942. The writing was on the wall for the Afrika Korps, and further Allied advances into Tunisia in 1943 won the war in desert.

The remaining Axis troops retreated back to Sicily, which soon became the next target for Britain and the USA. From Sicily, the Allies could then land on the Italian mainland. This would leave fascist Italy on the brink of defeat and crush Mussolini's regime.

As such, the Allies landed at and occupied Sicily. However, a number of Axis troops were able to retreat into Italy. Britain and the USA landed their armies at various points along the Italian coastline. After the Allies had gained a foothold in Italy, the Italian king soon removed Mussolini from his post and established an armistice with the Allies.

While the Italian armies were more quickly defeated, the Germans began to re-enforce Italy with strong divisions. A mission to rescue Mussolini ensured the campaign continued after Italy had established an armistice, and the Allies began to advance northwards. This advance ground to a halt as the Allied soldiers reached the hills of Monte Cassino.

The Germans had dug-in and established effective defenses on the high ground of Monte Cassino. With artillery positions set up there, Monte Cassino became a Nazi stronghold.

The battle began in December 1943 as Commonwealth and U.S. troops advanced towards the Gustav Line. Early advances surrounded Monte Cassino to the north, west and south. However, not until January 17 did the first Allied wave of attacks at Monte Cassino begin.

To make sure the line was held, Germany sent reinforcements. The first wave of Allied strikes at Monte Cassino failed to penetrate the Gustav Line. As such, by the end of January the battle was far from won.

The failure of the first battles convinced the Allies that the Germans had established a stronghold at the monastery on the peak of Monte Cassino. B-17 Flying Fortresses bombed the monastery and reduced it to rubble. In fact, the Nazis had not fortified at the abbey. Further Allied advances in February were also ineffective.[1]

The third phase of the Battle of Monte Cassino began on March 15. For this the Allies had planned preliminary bombing campaigns, which they hoped would pave the way for further Allied advances along the Rapido Valley. However, the loss of tanks during further advances undermined the Allies. Consequently, the Germans halted the Allies on the 22nd and held the line by the end of March.

Britain and the USA began to draft a new battle plan after March. Operation Diadem became the new plan that included troops from the Polish and French divisions in a flanking maneuver around the monastery. This began on May 11, and by May 13 the French had opened up a direct route to Rome. On the 17th German soldiers began to retreat from Monte Cassino, and on the 18th Polish troops occupied the ruins of the monastery. Here the soldiers raised Poland's flag and the Battle of Monte Cassino was over.

As the Allies broke out from Anzio, they advanced towards Rome. Rome was then occupied by the Allies, while Nazi troops retreated further northwards. The Italian Campaign continued into 1945 when the remaining German armies in Italy surrendered.