Waiting for the German attack

 <p>A mixed force of New Zealand, Australian, and Greek waited for the expected German attack. "During the first quarter of 1941, the German army to attack Greece was assembled. They called the operation to attack Greece "Operation Marita". "A directive to attack Greece was issued on 13 December 1940". There was concern about "British air bases that threatened Romanian oil fields and Italy". The battle in Albania had an uncertain outcome that could threaten later operational plans.

The situation in Yugoslavia changed with the success of the coup. That caused the dates for attacking Russia to change among other operations. It also increased the forces that would be necessary for the Greek Campaign. They needed to treat Yugoslavia with sufficient harshness so that Turkey would be frightened into staying out of the war. Part of the plan included bombing Belgrade to destroy the city. The Germans assumed that Croatia would come into the war on their side when the attack happened. The Soviets had signed a treaty with Yugoslavia, but the Germans were undeterred by that event. 

The German 12th Army was assigned to conduct the operation against Greece. The 12th Army had been involved in France in 1940 and was beginning to assemble in Romania in late 1940. The 12th Army would have to cross the Danube River. It would be up to the 12th Army to construct ways to cross the river. One of the challenges was that in late February, the Danube was blocked by ice. With the ice as an issue, the 12th Army only had time to build three bridges before they moved into Bulgaria. They were only able to move into Bulgaria for some days after 2 March. 

HItler wanted the attack on Greece to begin on 1 April, but Field Marshal List would be the one to set the exact dates for the operation. The new requirement to occupy Yugoslavia meant that they needed to add more forces for the attack. This is based on the account in "Greece Crete and Syria" by Gavin Long.