Eighth Army (United Kingdom) in the context of "18th 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).

The Sanusi order or Sanusiyyah (Arabic: السنوسية, romanized: as-Sanūssiyya) are a Muslim political-religious Sufi order (tariqa) in Libya and North Africa founded in Mecca in 1837 by Muhammad ibn Ali al-Sanusi.

During World War I the Senusi order fought against both Italy and Britain. During World War II, the order provided support to the British Eighth Army in North Africa against Nazi and Fascist Italian forces. The founder's grandson became King Idris I of Libya in 1951. The 1969 Libyan revolution led by Muammar Gaddafi overthrew him, ending the Libyan monarchy. The movement remained active despite persecution by Gaddafi's government, and its cultural legacy continues to this day in Libya, centered on Cyrenaica.

The Western Desert campaign (Desert War) took place in the deserts of Egypt and Libya and was the main theatre in the North African campaign of the Second World War. Military operations began in June 1940 with the Italian declaration of war and the Italian invasion of Egypt from Libya in September. Operation Compass, a five-day raid by the British in December 1940, was so successful that it led to the destruction of the Italian 10th Army (10ª Armata) over the following two months. Benito Mussolini sought help from Adolf Hitler, who sent a small German force to Tripoli under Directive 22 (11 January). The Afrika Korps (Generalleutnant Erwin Rommel) was formally under Italian command, as Italy was the main Axis power in the Mediterranean and North Africa.

In the spring of 1941, Rommel led Operation Sonnenblume, which pushed the Allies back to Egypt except for the siege of Tobruk at the port. At the end of 1941, Axis forces were defeated in Operation Crusader and retired again to El Agheila. In early 1942 Axis forces drove the Allies back again, then captured Tobruk after the Battle of Gazala but failed to destroy their opponents. The Axis invaded Egypt and the Allies retreated to El Alamein, where the Eighth Army fought two defensive battles, then defeated the Axis forces in the Second Battle of El Alamein in October 1942. The Eighth Army drove Axis forces out of Libya to Tunisia, which was invaded from the west by the Allied First Army in Operation Torch. In the Tunisian campaign the remaining Axis forces surrendered to the combined Allied forces in May 1943.

The Desert Air Force (DAF), also known chronologically as Air Headquarters Western Desert, Air Headquarters Libya, the Western Desert Air Force, and the First Tactical Air Force (1TAF), was an Allied tactical air force created from No. 204 Group RAF under RAF Middle East Command in North Africa in 1941 to provide close air support to the British Eighth Army against Axis forces. Throughout the Second World War, the DAF was made up of squadrons from the Royal Air Force (RAF), the South African Air Force (SAAF), the Royal Australian Air Force (RAAF), the United States Army Air Forces (USAAF) and other Allied air forces.

In October 1941, the Western Desert Air Forces had 16 squadrons of aircraft (nine fighter, six medium bomber and one tactical reconnaissance) and fielded approximately 1,000 combat aircraft by late 1941. By the time of the Second Battle of El Alamein, the DAF fielded 29 squadrons (including nine South African and three USAAF units) flying Boston, Baltimore and Mitchell medium bombers; Hurricane, Kittyhawk, Tomahawk, Warhawk and Spitfire fighters and fighter-bombers. There were over 1,500 combat aircraft, more than double the number of aircraft the Axis could field.

The Battle of Mersa Matruh was fought from 26 to 29 June 1942, following the defeat of the Eighth Army (General Sir Claude Auchinleck) at the Battle of Gazala and was part of the Western Desert Campaign of the Second World War. The battle was fought with the German–Italian Panzer Army Afrika (Panzerarmee Afrika (Generalfeldmarschall Erwin Rommel). The Eighth Army comprised X Corps and XIII Corps.

The battle was fought during the pursuit by the Panzerarmee of the Eighth Army as it retreated into Egypt. Rommel intended to defeat in detail (one after the other) the British infantry formations, before they had a chance to regroup. The fortress port of Mersa Matruh and 6,000 prisoners were captured, along with a great deal of supplies and equipment. The Axis cut off the line of retreat of X Corps and XIII Corps but was too weak to stop the British from breaking out.

The Second Battle of El Alamein (23 October – 11 November 1942) was a battle of the Second World War that took place near the Egyptian railway halt of El Alamein. The First Battle of El Alamein and the Battle of Alam el Halfa had prevented the Axis from advancing further into Egypt.

In October 1942 Lieutenant-General Bernard Montgomery, commander of Eighth Army, opened his offensive against the Axis forces. In a 13-day battle the Axis Panzerarmee Afrika was crushed and forced to retreat from Egypt and Libya to the borders of Tunisia. The Allied victory at El Alamein was the beginning of the end of the Western Desert Campaign.

The siege of Tobruk (/təˈbrʊk, toʊ-/) took place between 10 April and 27 November 1941, during the Western Desert campaign (1940–1943) of the Second World War. An Allied force, consisting mostly of the 9th Australian Division, commanded by Lieutenant-General Leslie Morshead, was besieged in the North African port of Tobruk by German and Italian forces. The tenacious defenders quickly became known as the Rats of Tobruk. After 231 days, they were finally relieved by the British Eighth Army.

In late 1940, the Allies had defeated the Italian 10th Army during Operation Compass (9 December 1940 – 9 February 1941) and trapped the remnants at Beda Fomm. On 22 January 1941, Tobruk's Italian garrison surrendered. But in early 1941, much of the British Western Desert Force was sent to the Greek and Syria–Lebanon campaigns, leaving only a skeleton force short of equipment and supplies.