7 October
Balkans, Romania
German forces enter Romania on the pretext of helping to train the army of the fascist Iron Guard government. Germany’s principal motive is to occupy the Ploesti oil fields.
9 October
Politics, Britain
Winston Churchill succeeds Neville Chamberlain, the former prime minister, as Conservative Party leader. Churchill was initially an unpopular figure in the party but his war leadership has gone a long way to reverse this.
12 October
Politics, Germany
Hitler postpones Operation Sealion until spring 1941.
15 October
Politics, Italy
The Italian war council decides to invade Greece. Italy plans not to tell its Axis partner Germany about the operation, which is scheduled to commence at the end of October.
16-19 October
Politics, Japan
The Dutch East Indies agrees to supply 40 percent of its oil production to Japan for six months despite British attempts to obstruct this.
18 October
Politics, Vichy France
The puppet Vichy regime introduces anti-Semitic laws.
28 October
Balkans, Greece
Italy issues an ultimatum to Greece demanding the right to occupy the country for the war’s duration. Before the ultimatum expires, eight divisions, led by General Sabasiano Visconti-Prasca, attack from Albania. Italy hopes for a rapid advance to rival Germany’s conquests, but mountainous terrain and the absence of maps for commanders hamper the invasion. The winter weather limits air support and thousands die of cold. Greek forces, under General Alexander Papagos, the commander-in-chief, mount stiff resistance.
30-31 October
Mediterranean, Crete
British forces occupy the Greek island.