Battle of Rethymno The Battle of Rethymno , also known as the Battle of Retimo , was a battle during World War II on the Greek island of Crete . It began on the morning of 20 May 1941 , when Nazi Germany launched an airborne invasion of Crete under the codename Unternehmen Merkur ( " Operation Mercury " ) . Australian and Greek forces defended the Rethymno airfield . Background . Rethymno , a town on the north coast of Crete , was important to the military defense of Crete by the British and Commonwealth force because an airport had been completed about east of the town shortly before the battle . British and Commonwealth forces had been forced out of Greece by the Germans and had retreated to Crete . While there were between 27 , 000 – 28 , 000 troops in Crete to defend it , most were only lightly armed because the heavier equipment had been left in Greece . Although the Germans were able to dominate the skies , the British Royal Navy had control of the sea . The German plan was to use paratrooper s and glider s to send forces down by air . Before the battle . The Australian 2 / 1st and 2 / 11th Battalion s , supported by elements from Australian artillery , medical , engineer and signals units , as well as the Greek 4th and 5th Regiments , took up positions in the hills south of the airfield . This was in anticipation of an airborne German attack . Australian Lieutenant Colonel Ian Campbell , commanding the 2 / 1st Battalion , was overall commander of the Rethymno units and had been charged to defend the area . The defence was based around two hills that overlooked the airstrip . The day before the battle , a lone German plane flow over Rethymno on a reconnaissance mission . Against orders , a Bren gun position shot it down . Campbell obtained a code book and photos of the area from the crashed aircraft . From the photos , Campbell could see that part of the defences were hidden by trees and would not be known by the Germans . The code was used by the commander of the 2 / 11th Battalion to order supplies . The offensive . German paratroopers , the Fallschirmjäger , landed in three areas on 20 May : Maleme , Rethymno and Iraklion . The German operation was a three - pronged strike . The central assault , codenamed " Aris " , focused on Rethymno . Maleme , on the west of the island , quickly fell . The German 2nd Parachute Rifle Regiment , numbering two battalions and with detachments from divisional support troops , were to land and attack Rethymno . The paratroopers had expected to take the airfield easily , but were surprised when they found it heavily defended . Preceded by heavy aerial bombing , the initial German landing was disorganised , with seven transport Junkers Ju 52 s shot down and the paratroopers receiving heavy casualties . However , the paratroopers did manage to capture the hill that 2 / 1st Battalion was positioned on . German forces were also able to block the roads east and west of Rethymno . On 22 May , after two failed counterattacks , a third counterattack organised in four columns by the Australians drove the Germans off the hill , who took up positions in an old olive oil factory at Stavromenos . While the German paratroopers had no heavy equipment or armour , the Australian troops had the use of two Matilda tanks as well as artillery . However , the two tanks were not used effectively , as both tank crews were originally captured after the tanks were trapped in ditches . Control of one was later regained , and it was used to support the infantry with a further attack by the Australians , which drove the Germans out of the factory on 26 May , who later retreated to Heraklion . Another group of German paratroopers made a landing to the west of the airfield . However , their landings were scattered , and some landed on top of the 2 / 11th Battalion with others dropping in the nearby plain . Those that were not intercepted or captured moved towards the town of Rethymno itself . Finding Rethymno defended by Cretan police , the Germans took up defensive positions in a ridge that ran from the mountains to the sea . From 22 – 28 May , Australian and Greek troops moved together against the German paratroopers in this ridge . Coordination between the Australians and the Greeks proved difficult , and at one point , the lesser - trained Greek soldiers opened fire early and warned the Germans of the incoming Australian attack . There was no communication with other Allied units on Crete , so Campbell was unaware as to what had been happening with the overall Allied effort . An attack was made against Pervolia on 27 May , with the use of the two Matilda tanks ( both of which had now been recovered from their immobilised positions ) . When one tank was knocked out by anti - tank guns and the other was hit by a mine , the attack stalled . The assault on Pervolia again proceeded on 28 May , and this time the town was taken . By this time , the Australians were running low on supplies and were forced to withdraw after holding Pervolia for only a short while . On 29 May , the Greeks abandoned their positions and the Australians were forced to reduce the size of their perimeter . While the battles for Rethymno and Heraklion had been more successful , Maleme had been lost to the Germans . The German control of the airstrip there , coupled with their total air superiority , meant that the Luftwaffe could now land infantry and equipment by plane . At this time , reinforcements from Maleme arrived to assist the original Fallschirmjäger , including German panzers , and the Australians soon found themselves outgunned and surrounded . Surrender . With the Greek troops gone , a lack of food , dwindling supplies , no contact with the rest of the Allied troops on Crete ( who were in fact surrendering or retreating ) , and the appearance of additional German troops , Campbell chose to order the Rethymno group to surrender to the Germans . However , Major Sandover , in charge of the 2 / 11th Battalion , instructed his men that they could either surrender or evade capture . Many chose the latter by hiding in the hills , some protected by local Cretans who were under threat of being executed by the Germans . Of the 2 / 11th Battalion , 13 officers and 39 other ranks escaped to Egypt .