The German strategy: Plan "Marita"
In reality, the decision for the German invasion had already been taken by the Axis camp. The approval of the German operation in the Balkans, with the intention of passing through Bulgaria in order to occupy Greece (Plan Marita), had taken place in Berlin since mid-December 1940.
Although Hitler had from the first moment declared his desire to avoid conflict in the Balkans, the new strategic conditions dictated a different course of action. The failure of the Italian attack on Greece had become apparent by the end of 1940 and had created a new open front for the Axis, at the same time when the German forces had failed to overcome the resistance of Britain and the Italian troops were retreating in North Africa.
Furthermore, the unsuccessful negotiations between Hitler and the Russian Foreign Minister Molotov in Berlin in November 1940 had convinced the German dictator that the time of the showdown with the Soviet Union was nearing. Consequently, he wished to create the best possible strategic conditions for the success of Operation Barbarossa against the Soviet Union. In this sense, it was imperative that the Balkans be drawn in the Axis sphere of influence, overcoming the resistance of the Greek forces in Albania and thus blocking a bridge of communication for the British with North Africa.