The name Tre Venezie was created in 1863 by historical linguist Graziadio Isaia Ascoli (from Gorizia). The area included what would become by 1866-1919 the three Italian regions of Venezia Euganea, Venezia Giulia and Venezia Tridentina. This territory was named after Roman region of Venetia et Histria.
Nowadays the name Triveneto is more commonly used, and it includes the three Italian regions of Veneto, Friuli-Venezia Giulia and Trentino-Alto Adige/Südtirol, together with the provinces of Belluno, Bolzano, Gorizia, Padua, Pordenone, Rovigo, Trento, Treviso, Trieste, Udine, Venice, Verona, Vicenza.
The area was fully under the Austrian rule in 1863; Italy annexed Venezia Euganea in 1866, following the Third Italian War of Independence and a controversial plebiscite (see Venetian Nationalism page); Venezia Giulia and Venezia Tridentina passed under the Italian rule in 1919, following the end of World War I.
After World War II Italy retained the most part of Tre Venezie, but lost upper Isonzo valley (together with the eastern part of Gorizia, today called Nova Gorica), the city of Fiume, most part of Carso region and most part of Istria to Yugoslavia. The areas of Trieste (Zone A) and north-west Istria (Zone B) were formed in the Free Territory of Trieste: in 1954, Italy annexed back Zone A, while Zone B was ceded to Yugoslavia.
This territory distinguish itself for the legacy of the Austrian culture and administration, as well for the close ties with the German and Slavic worlds. It has anyway itself a great and ancient cultural history, dating back to the people which inhabited the area before and during the Roman Empire (Euganei, ancient Veneti, Raeti, Carni and Cenomani); to the Medieval duchies of Bavaria and Carinthia, Patriarchate of Aquileia and comuni; to the Republic of Venice and the Austrian Empire.
Presently Italian is used as the official language in all the regions, but together with local languages which are usually spoken by the population: Venetian, Friulian, German, Slovene, in their several dialects. German is a co-official language in Trentino-Alto Adige/Südtirol; Slovene and Friulian are official languages in Friuli-Venezia Giulia.