The British Government anticipated an invasion of Greece by the Germans in 1941 and decided to send troops to support the Greeks, who were already engaged against the Italians in Albania. The 2nd New Zealand Division was one of a number of Allied units dispatched to Greece in early March. The 4th Brigade was tasked with the defence of the Aliakmon Line in northern Greece, with the 20th Battalion preparing and manning the defences along the western end of the line. On 6 April, the Germans invaded Greece and their advance was so rapid that it quickly threatened the Florina Gap. The 4th Brigade was withdrawn to the Servia Pass where it manned defences that were superior to its previous positions.