Italian Occupation of Yugoslavia
On 18 April 1941, in line with the Italian Fascist Party political administration under Mussolini, once military control had been established in a territory, the administration reverted to civilian (fascist) control. The province of Ljubljana was administered by the High Commissioner, Emilio Grazioli, together with many fascist officials from the Italian province of Venezia-Giulia. This was part of an Italification of the Province, including the use of Yugoslav stamps overprinted in the name of the Commission. On 3 May 1941, this region was incorporated into Italy as a Province, with the use of Italian 'Imperiale' stamps of the period.
The Occupation of Yugoslavia once again enabled the Italians to renew their claims to the territory of Fiume, and in May 1941 the area surrounding Fiume, including Arbe and Veglia Islands, was occupied and later annexed to the pre-existing Province of Fiume. A number of overprinted issues on the stamps of Yugoslvia were produced, including the initials ZOFK (Fiume Kupa Occupied Zone), MAS (Memento Avdere Semper – Remember always be daring), and several other Commemorative and Charity issues.
The Kingdom of Yugoslavia was created from the Kingdom of Serbs & Croats with the addition of Slovenia, with the same cracks effecting the unity of the county, manifesting themselves in ethnic divisions within the armed forces.
In October 1940, as part of the establishment of the 'New Roman Empire', Mussolini attacked Greece, with the goal of establishing a puppet state under Italian influence. This new Greek state would permit the Italian annexation of the Ionian and Aegean Island groups. These islands were claimed on the basis that they had once belonged to the Venetian Republic and the Venetian client state of Naxos. In addition, the Epirus and Acarnania regions were to be separated from the rest of the Hellenic territory, and the Italian-controlled Kingdom of Albania was to annex territory along the Hellenic north-western frontier. In the grand scheme Greece would be compensated for its extensive territorial losses, by allowing it to annex the British Crown Colony of Cyprus, after the war had reached its 'victorious conclusion'.
The initial occupation of Greece proved a complete disaster for the Italians, who were driven back into Albania. Hitler was enraged by Mussolini's failure and was determined to save face for the 'Axis' alliance, at the same time preventing the British (in Greece) having a platform to bomb German oilfields in Rumania, postponing the invasion of Russia and coming to the aid of the Italians. Despite brave resistance to the German onslaught, the Greek generals decided to sue for an 'honourable' peace. The defeated British forces retreated, and the victorious Axis allies staged their triumphal parade through Athens.
Following agreements with Hungary, Romania and Bulgaria that they would join the Axis, Hitler put pressure on Yugoslavia to join the Tripartite Pact. The Regent, Prince Paul of Yugoslavia, succumbed to this pressure on March 25, 1941. However, this move was deeply unpopular amongst the anti-Axis Serbian public and military. A coup d'état was launched on March 27, 1941 by Serbian military officers, and Prince Paul was replaced on the throne by King Peter II of Yugoslavia.
Despite its sizeable troop numbers and quantities of more modern armaments, the Royal Yugoslav Army suffered badly from the Serbo-Croat schism in Yugoslav politics. 'Yugoslav' resistance to the invasion collapsed overnight, mainly because of the subordinate national groups; Slovenes and Croats were not prepared to fight to defend the newly created "Serbian" Kingdom of Yugoslavia. The only effective opposition to the invasion was from wholly Serbian units within the borders of Serbia itself. The most striking example of this disunity was on April 10, 1941, when some of the units in the Croatian-manned 4th and 7th Armies mutinied, and the same day, a newly formed Croatian government hailed the entry of the Germans into Zagreb. (Many of these deeply engrained schisms are still manifesting themselves to the present day).
The Italian Second Army crossed the border soon after the Germans. The Second Army faced the Yugoslavian Seventh Army, but the Italians encountered limited resistance and occupied parts of Slovenia, Croatia and the coast of Dalmatia. In addition to the Second Army, Italy had four divisions of the Ninth Army on the Yugoslavian border with Albania. Around 300 Ustaše (Croatian Fascist) volunteers, under the command of Ante Pavelić, accompanied the Italian Second Army during the invasion and set up an independent Croate state. (Stamps of Italy overprinted 'N.D. Hrvatska' were issued at Sebenico and Spalato).
On April 17, 1941, Yugoslavia surrendered after eleven days of fighting on multiple fronts. The country was subsequently divided amongst Germany, Hungary, Italy and Bulgaria.