The earliest mention of Udine can be found in a document dating back to 983; it is a charter with which Emperor Otto II granted the castle of Udine (together with those of other four neighboring localities) to the Patriarch of Aquileia. Yet excavations carried out in different times trace its history back to many centuries before. It may be taken for granted that during the second millennium B.C. there was already a more or less steady settlement in the place.
The second important date in the evolution of Udine was the year 1223, when Patriarch Berthold of Andechs-Merania obtained from Emperor Frederick Il the confirmation of his sovereign rights and granted Udine the market which in a few years was removed from Old Market Place to New Market Square (piazza Matteotti), so rapid was the growth of the town.
Yet the aspect of the city was sharply modeled only after 1420 when Udine and the whole of Friuli were part of the Venetian Republic. "Under the rule of Venice our land followed the destiny of the state it was linked to: we would mention several raids by the Turks (from 1472 to 1499), the war between the Republic and Emperor Maximilian (1508-1514), the war of Gradisca (1615-1617) between the Venetians and the Imperials. In 1797 Friuli was occupied by the Napoleonic troops and the following year, on account of the Treaty of Campoformio, it came under the rule of the House of Austria.
Yet defeated several times by the French it resumed the permanent domination of Friuli only in 1813. After the unsuccessful liberal rising of 1848, on the 2nd of October 1866 the Province of Udine was annexed to the Reign of Italy" (Rizzi).
During World War 1 (1915-1918) Udine was the seat of the Italian Supreme Command. In 1963 the city and its Province together with Trieste, Gorizia and Pordenone constituted Friuli-Venezia Giulia, a self-governing Region with Special Ordinance.