World War II

====European occupations and agreements====
[[File:Bundesarchiv Bild 183-R69173, Münchener Abkommen, Staatschefs.jpg|thumb|left|[[Neville Chamberlain|Chamberlain]], [[Édouard Daladier|Daladier]], [[Adolf Hitler|Hitler]], [[Benito Mussolini|Mussolini]], and [[Galeazzo Ciano|Ciano]] pictured just before signing the [[Munich Agreement]], 29 September 1938]]

In Europe, Germany and Italy were becoming more aggressive. In March 1938, Germany [[Anschluss|annexed Austria]], again provoking [[appeasement|little response]] from other European powers.{{sfn|Collier|Pedley|2000|p=144}} Encouraged, Hitler began pressing German claims on the [[Sudetenland]], an area of [[Czechoslovakia]] with a predominantly [[Germans|ethnic German]] population. Soon the United Kingdom and France followed the appeasement policy of British Prime Minister [[Neville Chamberlain]] and conceded this territory to Germany in the [[Munich Agreement]], which was made against the wishes of the Czechoslovak government, in exchange for a promise of no further territorial demands.{{sfn|Kershaw|2001|pp=121–122}} Soon afterwards, Germany and Italy forced Czechoslovakia to [[First Vienna Award|cede additional territory]] to Hungary, and Poland annexed the [[Trans-Olza]] region of Czechoslovakia.{{sfn|Kershaw|2001|p=157}}

Although all of Germany's stated demands had been satisfied by the agreement, privately Hitler was furious that British interference had prevented him from seizing all of Czechoslovakia in one operation. In subsequent speeches Hitler attacked British and Jewish "war-mongers" and in January 1939 [[Plan Z|secretly ordered a major build-up of the German navy]] to challenge British naval supremacy. In March 1939, [[Occupation of Czechoslovakia (1938–1945)|Germany invaded the remainder of Czechoslovakia]] and subsequently split it into the German [[Protectorate of Bohemia and Moravia]] and a pro-German [[client state]], the [[Slovak Republic (1939–1945)|Slovak Republic]].{{sfn|Davies|2006|loc=pp. 143–44 (2008 ed.)}} Hitler also delivered an [[1939 German ultimatum to Lithuania|ultimatum to Lithuania]] on 20 March 1939, forcing the concession of the [[Klaipėda Region]], formerly the German ''Memelland''.{{sfn|Shirer|1990|pp=461–462}}

[[File:Bundesarchiv Bild 183-H27337, Moskau, Stalin und Ribbentrop im Kreml.jpg|right|thumb|upright|German Foreign Minister [[Joachim von Ribbentrop]] (right) and the Soviet leader [[Joseph Stalin]], after signing the [[Molotov–Ribbentrop Pact]], 23 August 1939]]
Greatly alarmed and with Hitler making further demands on the [[Free City of Danzig]], the United Kingdom and France [[Anglo-Polish alliance#British assurance to Poland|guaranteed their support for Polish independence]]; when [[Italian invasion of Albania|Italy conquered Albania]] in April 1939, the same guarantee was extended to the [[Kingdom of Romania|Kingdoms of Romania]] and [[Kingdom of Greece|Greece]].{{sfn|Lowe|Marzari|2002|p=330}} Shortly after the [[Franco-Polish alliance|Franco]]-[[Anglo-Polish alliance|British]] pledge to Poland, Germany and Italy formalised their own alliance with the [[Pact of Steel]].{{sfn|Dear|Foot|2001|p=234}} Hitler accused the United Kingdom and Poland of trying to "encircle" Germany and renounced the [[Anglo-German Naval Agreement]] and the [[German–Polish declaration of non-aggression]].{{sfn|Shirer|1990|p=471}}

The situation became a crisis in late August as German troops continued to mobilise against the Polish border. On 23 August the Soviet Union signed [[Molotov–Ribbentrop Pact|a non-aggression pact]] with Germany,{{sfn|Shore|2003|p=108}} after tripartite negotiations for a military alliance between France, the United Kingdom, and Soviet Union had stalled.<ref>{{Cite journal |last1=Watson |first1=Derek |year=2000 |title=Molotov's Apprenticeship in Foreign Policy: The Triple Alliance Negotiations in 1939 |journal=Europe-Asia Studies |volume=52 |issue=4 |pages=695–722 |doi=10.1080/713663077 |jstor=153322 |s2cid=144385167}}</ref> This pact had a secret protocol that defined German and Soviet "spheres of influence" (western [[Second Polish Republic|Poland]] and Lithuania for Germany; [[Territories of Poland annexed by the Soviet Union|eastern Poland]], Finland, [[Estonia]], [[Latvia]] and [[Bessarabia]] for the Soviet Union), and raised the question of continuing Polish independence.{{sfn|Dear|Foot|2001|p=608}} The pact neutralised the possibility of Soviet opposition to a campaign against Poland and assured that Germany would not have to face the prospect of a two-front war, as it had in World War{{nbsp}}I. Immediately afterwards, Hitler ordered the attack to proceed on 26 August, but upon hearing that the United Kingdom had concluded a formal mutual assistance pact with Poland and that Italy would maintain neutrality, he decided to delay it.<ref>{{cite web|url=https://www.ibiblio.org/hyperwar/USA/DAP-Poland/Campaign-II.html#chapter5|title=The German Campaign In Poland (1939)|access-date=29 October 2014|archive-url=https://web.archive.org/web/20140524013551/https://www.ibiblio.org/hyperwar/USA/DAP-Poland/Campaign-II.html#chapter5|archive-date=24 May 2014|url-status=live}}</ref>

In response to British requests for direct negotiations to avoid war, Germany made demands on Poland, which served as a pretext to worsen relations.<ref name=ww2db_com>{{cite web |url=https://ww2db.com/battle_spec.php?battle_id=162 |title=The Danzig Crisis |website=ww2db.com |access-date=29 April 2016 |archive-url=https://web.archive.org/web/20160505010109/https://ww2db.com/battle_spec.php?battle_id=162 |archive-date=5 May 2016 |url-status=live}}</ref> On 29 August, Hitler demanded that a Polish [[plenipotentiary]] immediately travel to Berlin to negotiate the handover of [[Gdańsk|Danzig]], and to allow a [[referendum|plebiscite]] in the [[Polish Corridor]] in which the German minority would vote on secession.<ref name=ww2db_com /> The Poles refused to comply with the German demands, and on the night of 30–31 August in a confrontational meeting with the British ambassador [[Nevile Henderson]], Ribbentrop declared that Germany considered its claims rejected.<ref name=ibiblio1939>{{cite web |title=Major international events of 1939, with explanation |url=https://www.ibiblio.org/pha/events/1939.html |publisher=Ibiblio.org |access-date=9 May 2013 |archive-url=https://web.archive.org/web/20130310103815/https://www.ibiblio.org/pha/events/1939.html |archive-date=10 March 2013 |url-status=live}}</ref>