World War II

====Mediterranean (1940–1941)====
{{Main|Mediterranean and Middle East theatre of World War II}}

In early June 1940, the Italian ''Regia Aeronautica'' [[Siege of Malta (World War II)|attacked and besieged Malta]], a British possession. From late summer to early autumn, Italy [[Italian invasion of British Somaliland|conquered British Somaliland]] and made an [[Italian invasion of Egypt|incursion into British-held Egypt]]. In October, [[Greco-Italian War|Italy attacked Greece]], but the attack was repulsed with heavy Italian casualties; the campaign ended within months with minor territorial changes.{{sfn|Clogg|2002|p=118}} To assist Italy and prevent Britain from gaining a foothold, Germany prepared to invade the Balkans, which would threaten Romanian oil fields and strike against British dominance of the Mediterranean.<ref>{{Harvnb|Evans|2008|pp=146, 152}}; {{Harvnb|US Army|1986|pp=[https://www.history.army.mil/books/wwii/balkan/20_260_1.htm 4–6]}}</ref>

[[File:Bundesarchiv Bild 101I-783-0109-11, Nordafrika, Panzer III in Fahrt.jpg|thumb|German [[Panzer III]] of the [[Afrika Korps]] advancing across the North African desert, April–May 1941]]
In December 1940, British Empire forces began [[Operation Compass|counter-offensives]] against Italian forces in Egypt and [[East African campaign (World War II)|Italian East Africa]].{{sfn|Jowett|2001|pp=9–10}} The offensives were successful; by early February 1941, Italy had lost control of eastern Libya, and large numbers of Italian troops had been taken prisoner. The [[Regia Marina|Italian Navy]] also suffered significant defeats, with the Royal Navy putting three Italian battleships out of commission after a [[Battle of Taranto|carrier attack at Taranto]], and neutralising several more warships at the [[Battle of Cape Matapan]].{{sfn|Jackson|2006|p=106}}

Italian defeats prompted Germany to [[Operation Sonnenblume|deploy an expeditionary force]] to North Africa; at the end of March 1941, [[Erwin Rommel|Rommel]]'s [[Afrika Korps]] [[Western Desert campaign|launched an offensive]] which drove back Commonwealth forces.{{sfn|Laurier|2001|pp=7–8}} In less than a month, Axis forces advanced to western Egypt and [[Siege of Tobruk|besieged the port of Tobruk]].{{sfn|Murray|Millett|2001|pp=263–276}}

By late March 1941, [[Bulgaria]] and [[Yugoslavia]] signed the [[Tripartite Pact]]; however, the Yugoslav government was [[Yugoslav coup d'état|overthrown two days later]] by pro-British nationalists. Germany and Italy responded with simultaneous invasions of both [[Invasion of Yugoslavia|Yugoslavia]] and [[German invasion of Greece|Greece]], commencing on 6 April 1941; both nations were forced to surrender within the month.{{sfn|Gilbert|1989|pages=174–175}} The airborne [[Battle of Crete|invasion of the Greek island of Crete]] at the end of May completed the German conquest of the Balkans.{{sfn|Gilbert|1989|pages=184–187}} Partisan warfare subsequently broke out against the [[World War II in Yugoslavia|Axis occupation of Yugoslavia]], which continued until the end of the war.{{sfn|Gilbert|1989|pages=208, 575, 604}}

In the Middle East in May, Commonwealth forces [[Anglo-Iraqi War|quashed an uprising in Iraq]] which had been supported by German aircraft from bases within Vichy-controlled [[Mandate for Syria and the Lebanon|Syria]].{{sfn|Watson|2003|p=80}} Between June and July, British-led forces [[Syria–Lebanon campaign|invaded and occupied the French possessions of Syria and Lebanon]], assisted by the [[Free France|Free French]].<ref>{{Citation|last=Morrisey|first=Will|chapter=What Churchill and De Gaulle learned from the Great War|date=2019|pages=119–126|publisher=Routledge|isbn=978-0-429-02764-2|doi=10.4324/9780429027642-6|title=Winston Churchill|s2cid=189257503}}</ref>