After the fall of mainland Greece, it became essential that the Germans take the Ally controlled island of Crete. From the island of Crete, the Allies controlled shipping in the Aegean Sea. From the air fields on the island the Allies could potentially raid the Romanian oil fields which the Germans relied on heavily. Hitler also needed Crete under German control in order to move forward towards Cyprus and the Egyptian Delta. Operation Mercury began on May 20, 1941. The plan was contingent on two waves of attacks quickly overtaking the islands air fields.
On the morning of May 20, unaware that Allied intelligence knew of the attack, German Fallschirmjager (paratroopers) began to drop on the Maleme air field. Many Germans were killed during their descent as Allied forces peppered the paratroopers from well concealed hiding places. Simultaneously another group of German paratroopers landed at Hania and the Souda Bay area. These groups also met with significant resistance from the Allies.
Unaware of the difficulties the first wave of paratroopers were facing, the second wave began their descent. These troops attempted landings at Heraklion and Rethymnon airfields. This wave of parachutists suffered greater devastation than the first. By the evening the Germans had not succeeded in taking any of the airfields. However, the Germans were making some progress at the Maleme field, taking the hill at the north end of the airfield.
During the night of May 20 – 21, the German and British Navies battled in the waters around Crete. The Germans succeeded in sinking one British destroyer and damaging two cruisers. After this initial evening battle, the German convoy continued on to the island where troops were awaiting supplies and reinforcements. However, at 23:00, the Germans were once again attacked by the British. This time the British succeeded in stopping the convoy.
On the morning of May 22 the German Luftwaffe attacked the British fleet. This battle ended in a German victory, changing the course of the battle for Crete. Paratroopers continued to land on the island, while troop carriers sailed into ports carrying men and supplies. The Allied forces persisted in battle despite the fact that the Germans now maintained air and sea superiority. Local rebels also fought to avoid German occupation. Greek men, women and children fought valiantly using whatever means available; including pans, shovels, knives and bare hands.
After six more days of grueling battle, Allied forces began to evacuate the island of Crete on the night of May 28, 1941. The evacuation lasted three days. Approximately 16,500 troops escaped the island.