War came to the Balkans. German bomber planes flying over undefended Athens.

Italian aggression against Greece, which was launched on 28 October 1940, and resulted in humiliating blunder, had created a new political situation in the Balkans. To Great Britain it occurred as an opportunity to open another front of the war against the fascist "Axis", and engage vast human resources of the region in the military operations. Therefore, Great Britain declared its full support to the fighting Greece, and simultaneously embarked on diplomatic manoeuvres, aimed at creation of a block of Balkan countries - Greece, Yugoslavia and Turkey - blocked with England and her dominions.

At the same time the Balkans had absorbed attention of Germany, which was already preparing for the war with the USSR - the invasion was planned for May 1941. To the German leader, Adolf Hitler, the new situation in the Balkans constituted a serious menace to the southern wing of his forces designated to the operation Barbaroßa. Also, Balkan countries were considerable suppliers of food and raw materials to Germany. Therefore, they had to be subdued to the interests of the Third Reich, whether through diplomatic action, or direct armed aggression.

Germany headed towards that goal gradually. On 27 September 1940 in Berlin Germany, Italy and Japan concluded the Tripartite Pact, joint in November by Hungary and Romania. In the latter were immediately deployed German troops. Then came the turn of Bulgaria, subdued in February 1941, and the pressure on Yugoslavia began. But the political rapprochement with Yugoslavia had failed.

As to Greece, Hitler originally did not abandon hope that his mediation would "rebuke the Greeks without resorting to the force". Yet, already on 12 November 1940 he signed the Directive No.18, which provided for an operation against Greece from Bulgaria "if necessary". General provisions of the operation were detalized during next weeks within the framework of the plan codenamed Marita. It provided for concentration of the German 12th Army in Romania, its entry to Bulgaria, deployment along the Bulgaro-Greek frontier, and strike in the direction of Salonika. In March 1941 that army comprised 19 divisions, including 5 armoured ones.

Meanwhile Greece's situation in early spring of 1941 was difficult. Five months of the war with Italy, although successful, had exhausted materiel resources of that small and poor country, while the British aid was not too big. Although all the means and resources at hand were mobilized for the needs of the fighting army, it suffered from shortages of weapons, equipment, ammunition, transportation and medicines.

The Greek army, commanded by Gen. Aléxandros Papagos, numbered 500 thousand men. Out of 21 Greek divisions as many as 15 were deployed on the Albanian front in army groups Epirus and Western Macedonia. Others were deployed on the Bulgarian border or were still under training.

The perspective of a German invasion made Greece's situation completely hopeless. Arrival of the small British Expeditionary Corps at the end of March could not change it significantly. British forces included the 1st Armoured Brigade, New Zealand 2nd Division, Australian 6th Division, two artillery regiments, and auxiliary units. Altogether, concentrated in the W-Force commanded by Gen. Henry Maitland Wilson, they had about 60 thousand men.

Apart from the armies fighting in Albania, the Greeks had formed two new armies. The Army Eastern Macedonia, composed of 4.5 divisions, was deployed in the fortifications of the Metaxas Line, guarding the border with Bulgaria. The Army Central Macedonia, which comprised two Greek divisions and the British W-Force, had to assume defences along the western bank of the Vardar, with the front in north-east. Those two armies, however, had no operational or tactical communication, and could be easily cut off from each other, as well as from the Albanian front. And the weakest point of the deployment of the Greek forces was the assumption that the Germans will attack from Bulgaria, without violating of the neutrality of Yugoslavia.

However, on 6 April 1941 the left wing of the German 12th Army, simultaneously with the invasion of Yugoslavia, attacked Greece across the Yugoslav territory. Despite of substantial enemy superiority, the Army Eastern Macedonia, deployed on the line of modern fortifications built in rough mountainous terrain, repelled numerous enemy assaults in bloody four-days fights, inflicting heavy losses on the Germans. However, at the same time the German 2nd Armoured Division rolled southern Yugoslavia, turned southwards, and on 9 April occupied Salonika. This way the Army Eastern Macedonia was cut off from the rest of the Greek forces and forced to capitulate.

Further events developed at a lightning speed. German divisions in Yugoslavia advanced fast; on 9 April their XL Motorized Corps reached Bitola and created menace to the Army Central Macedonia, build around the British W-Force, which could be now cut off from the Army Epirus. To avoid that the Greco-British forces on 12 April started retreating to the River Aliakmon. However, the attempt to re-create the continuous front on the line from Mount Olympus in the east, along the River Aliakmon, and farther to the Lake Butrint in the west failed. The XL Corps, faster than the Greek and British infantry troops, moved from Bitola to Florina, and on 15 April wedged into the Greco-British defences on the Aliakmon. Army Central Macedonia collapsed, and its troops dispersed in the Pindus Mountains. In those circumstances the British Expeditionary Corps had no other choice but to keep retreating southwards.

Already on 13 April Gen. Wilson came to the conclusion that the Greek supreme command had lost the control of the situation, and the Greek army as a whole had lost its combat capabilities. Saving their own troops from the Greek catastrophe became the only task of the British from then on, and Wilson ordered them to withdraw to the line Thermopylae - Delfi. That order had decided about the final evacuation of the British troops from the European continent, since the W-Force was too weak to defend new positions alone, while Greek troops, using mostly animal transportation, would need weeks to pull out of Albania and Epirus. One hardly could expect that the motorized German units would lend them that time.

The British evacuation began on on 15 April. Within 5 days they retreated 150km and concentrated around Thermopylae. Main Greek forces, Army Epirus, with the remnants of the Armies Western Macedonia and Central Macedonia, remained in the north west region of Greece, in the mountains of Epirus and Pindus.

On 20 April the SS Brigade Leibstandarte Adolf Hitler reached Metsovon pass, the Army Epirus' only route of retreat to the south. The new commander of the army, Gen. Geórgios Tsolákoglou, signed there a cease-fire with the Germans. On 23 April in Salonika he signed the formal instrument of surrender of the Greek army. Soon later he became the prime-minister of the puppet Greek government.

The king of Greece, George II, who decided to continue the struggle, on 21 April left for Crete aboard a British seaplane. At night from 24 to 25 April began the evacuation of the remnants of the W-Force from continental Greece (operation Demon). The German design to destroy the British Expeditionary Corps in continental Greece had failed. The British evaded major encounters with the Germans.

On 26 April, German airborne troops took Corinth and cut the route of retreat of the British troops from Attica to the Peloponnese. Yet, the efficient operation of the British Mediterranean fleet let to evacuate most of the British troops; only some rear units were taken prisoners. Altogether in Greece the British lost 12 thousand men and all the heavy equipment. On 27 April the Germans entered Athens, and on 29 April completed occupation of the Peloponnese.