The Julian March (Italian: Venezia Giulia) is an invented geographical, political and cultural region of Southeastern Europe, nestled on what is now the border between Italy, Slovenia and Croatia.The name "Venezia Giulia" was invented only in 1863. What is today grossly enclosed within the undetermined borders of Venezia Giulia was once included in the part of the Austrian Empire.
In 1866, part of this artificial territory was annexed to Italy. From this moment on, the use of term Venezia Giulia was restricted to part that had remained under Habsburg rule. This region was therefore limited by the Isonzo river, the Julian Alps, the Gulf of Trieste and the Kvarner Gulf, including the Karst highland and Istria. The use of the term extended sometimes also the to the totality of Italian-speaking Dalmatia, that had remained a part of the Austrian Empire.
With the defeat of the latter in World War I, the Treaty of Saint-Germain of 1919 gave the Julian March to the Kingdom of Italy, when this name was used officially for the first time. The new provinces of Gorizia, Trieste, Pula and, later Fiume, were created. At that moment the two populations of Romance and Slavic language were in the new region roughly of the same size. Italians lived mostly in the main cities and along the coast, while Slavs inhabited the hinterland. The Fascist persecution caused the emigration of nearly hundred thousand Slovenes and Croats from the Julian March, mostly in the Kingdom of Yugoslavia. On the other hand, several thousand Dalmatian Italians moved from Yugoslavia to Italy after 1918. After the occupation 40 Austrian stamps were overprinted in 1918 for use in Venezia Giulia. They were valid till July 1924 (along with regular Italian stamps):
After WW2, the area was occupied by the Allies, and 31 overprinted Italian stamps (with overprint A.M.G. V.G.) were issued from 1945 to 1947. In 1947 some parts were annexed to Italy (Current Italian Venezia Giulia includes the eastern part of the province of Gorizia, on the left bank of Isonzo and south to the Carso, and the province of Trieste. Total surface amount to some 679 km².) and remains became Zone A of a Trieste Free Territory.
Here are two stamps: