Patriarchate of Aquileia in the context of "Udine"

The Peace of Turin of 1381 ended the War of Chioggia (1376–81), in which Venice, allied with Cyprus and Milan, had narrowly escaped capture by the forces of Genoa, Hungary, Austria, Padua and the Patriarchate of Aquileia. Venice had overcome this crisis, forcing the surrender of the Genoese fleet at Chioggia, fighting a second Genoese fleet to a standstill in the Adriatic, and turning Austria against Padua, thus forcing its most threatening landward opponent into retreat. However, the war had been extremely costly for Venice, and it was only able to secure peace by making major concessions to its opponents.

The Patria del Friuli (Latin: Patria Fori Iulii, Friulian: Patrie dal Friûl), also known as the Patriarchal State of Aquileia (Italian: Stato patriarcale di Aquileia), was the territory under the temporal (political) rule of the Patriarch of Aquileia, and one of the ecclesiastical states within the Holy Roman Empire. It was created in the second half of the 11th century, and existed up to the first half of the 15th century. As in the case of other ecclesiastical states, its territory was not identical with jurisdictional borders of the Patriarchate of Aquileia. In 1420, the Republic of Venice acquired and consequently annexed the territory, thus depriving the Patriarch of Aquileia of his temporal powers. Under Venetian rule, the region continued to be administered for some time under its own laws and customs.

The Patriarchate of Grado, also known as the Patriarchate of New Aquileia, was an episcopal see and ecclesiastical province in northeastern Italy, centered in Grado, on the northern coasts of the Adriatic Sea. It was created as a result of an internal schism within the ancient Patriarchate of Aquileia. In 568, after the Lombard conquest of Aquileia, patriarch Paulinus left the city and fled to the minor coastal, but better protected town of Grado, that still remained under the Byzantine rule. First patriarchs who resided in Grado continued to exercise their jurisdiction over bishops in Lombard-held parts of the province, but at the very beginning of the 7th century a schism occurred, when bishops in Lombard regions elected their separate patriarch (Ioannes), who took residence in the old Aquileia, thus becoming rival to Candidianus of Grado. From that time, the region was divided between two distinctive jurisdictions: the Patriarchate of Old Aquileia in Lombard-held lands, and the Patriarchate of New Aquileia, with residence in Grado and jurisdiction over Byzantine possessions in the northern Adriatic (including Venice and Istria).

Initially, the patriarchs in Grado continued to claim the title of Patriarch of Aquileia, but in the early 700s it was gradually dropped and then officially changed to Patriarch of Grado. Throughout their history, the patriarchs of Grado, with the support of Venice and the Byzantines, fought military, politically, and ecclesiastically the patriarchs of old Aquileia, who were supported by the Lombards, and later the Carolingians and the Holy Roman Emperors.

The Patriarchate of Old Aquileia was created at the beginning of the 7th century, as a result of an internal schism within the Patriarchate of Aquileia. It was centered in the old Aquileia, that was held by the Lombards, while the rival Patriarchate of New Aquileia in Grado was under the Byzantine rule. Residence of the patriarchs of Old Aquileia was later moved, first to the city of Cormons, then to Cividale, and finally to Udine. Since 1077, patriarchs of Old Aquileia were also temporal lords of the Patriarchal State of Aquileia, that was annexed by the Venetian Republic in the first half of the 15th century, while the Patriarchate of Old Aquileia continued to exist as an ecclesiastical institution until 1751, when it was also abolished.