15th Army Group in the context of "Army group"

The Allied invasion of Italy was the Allied amphibious landing on mainland Italy that took place from 3 September 1943, during the Italian campaign of World War II. The operation was undertaken by General Sir Harold Alexander's 15th Army Group (comprising General Mark W. Clark's American Fifth Army and General Bernard Montgomery's British Eighth Army) and followed the successful Allied invasion of Sicily. A preliminary landing in Calabria (Operation Baytown) took place on 3 September, the main invasion force landed on the west coast of Italy at Salerno on 9 September as part of Operation Avalanche at the same time as a supporting operation at Taranto (Operation Slapstick).

Mark Wayne Clark (1 May 1896 – 17 April 1984) was a United States Army officer who fought in World War I, World War II, and the Korean War. He was the youngest four-star general in the U.S. Army during World War II.

During World War I, he was a company commander and served in France in 1918, as a 22-year-old captain, where he was seriously wounded by shrapnel. After the war, the future US Army Chief of Staff, General George C. Marshall, noticed Clark's abilities. During World War II, he commanded the United States Fifth Army, and later the 15th Army Group, in the Italian campaign. He is known for leading the Fifth Army when it captured Rome in June 1944, around the same time as the Normandy landings. He was also the head of planning for Operation Torch, the largest seaborne invasion at the time.

The Eighth Army was a field army of the British Army during the Second World War. It was formed as the Western Army on 10 September 1941, in Egypt, before being renamed the Army of the Nile and then the Eighth Army on 26 September. It was created to better control the growing Allied force based in Egypt and to direct its efforts to lift the siege of Tobruk via Operation Crusader.

It later directed Allied forces through the remaining engagements of the Western Desert campaign, oversaw part of the Allied effort during the Tunisian campaign and finally led troops throughout the Italian campaign. During 1943, it made up part of the 18th Army Group before being assigned to the 15th Army Group (later, the Allied Armies in Italy).

The Spring 1945 offensive in Italy, codenamed Operation Grapeshot, was the final Allied attack during the Italian Campaign in the final stages of the Second World War. The attack in the Lombard Plain by the 15th Allied Army Group started on 6 April 1945 and ended on 2 May with the surrender of all Axis forces in Italy.

The Allied Armies in Italy (AAI) was the title of the highest Allied field headquarters in Italy, during the middle part of the Italian campaign of World War II. In the early and later stages of the campaign the headquarters was known as the 15th Army Group; it reported to the Joint Allied command Allied Forces Headquarters (AFHQ), the theatre command for the Mediterranean theatre.

The 15th Army Group was renamed the Allied forces in Italy on 11 January 1944, then Allied Central Mediterranean Force on 18 January 1944 and finally the Allied Armies in Italy on 9 March 1944. The 15th Army Group was commanded by General Sir Harold R. L. G. Alexander until 11 December 1944. Lieutenant General Mark W. Clark, formerly the commander of the U.S. Fifth Army, then took command and the headquarters title was changed back to the 15th Army Group.