Ulrich II von Treven

Ulrich II (Latin: Voldoricus)
Patriarch of Aquileia
Aquileian denaro with a bust of Ulrich standing facing holding Gospel and crosier
Installed	1161
Term ended	1181
Predecessor	Pellegrino di Ortenbourg
Successor	Godfrey of Hohenstaufen
Personal details
Died	1182.04.01
Nationality	Austrian

Ulrich II von Treven was Patriarch of Aquileia in northern Italy from 1161 to 1181. He supported Frederick I, Holy Roman Emperor, (1122–1190) in his unsuccessful struggle for supremacy over the northern Italian states and the papacy. He was also involved in a dispute over jurisdiction with the Patriarch of Grado where he was ultimately successful.

Ulrich was the son of Count Wolfrad I von Treffen, ruler of the town of Treffen in Austria. His mother Hemma was the daughter of Margrave Starchand. Ulrich became Patriarch of Aquileia in 1161, succeeding Pellegrino di Ortenbourg.

The metropolitan sees of Aquileia and Grado had long been rivals. Their dispute dated to the invasion of the Huns, when the Patriarch of Aquileia took refuge in Grado. He brought the relics of two saints that Saint Mark the Evangelist had baptized. Grado claimed this showed that ecclesiastical authority had been transferred to the "new Aquileia". In 1024 Poppo of Treffen, patriarch of Aquileia, used force to subjugate Grado at a time when the Patriarch Ursus of Grado and the doge Otto Orseolo of Venice were in exile. He reclaimed the relics of saints Hermagoras and Fortunatus. Three years later Pope John XIX declared that Grado was just a parish of Aquileia, which was metropolitan of all Venice. However, in 1044 Pope Benedict IX recognized the Patriarch Ursus of Grado as head of the New Aquileia, demoting the prelate of Aquileia to bishop of Friuli. In 1053 Pope Leo IX recognized Grado as metropolitan of all of Venetia and Istria.

In 1155 Pope Adrian IV granted the patriarch of Grado jurisdiction over parts of the coast of Dalmatia, causing renewed tension.Frederick Barbarossa, the Holy Roman Emperor, aimed to bring northern Italy into his domains. Barbarossa entered Italy with his armies in 1154, and in 1161 established control of the mainland around Venice. In 1162, while Venice was involved in a war with Padua and Ferrara, Patriarch Ulrich of Aquileia attacked Grado. Ulrich led forces from the region of Friuli into Grado, which he declared to be a precinct of Aquileia.Enrico Dandolo, the Patriarch of Grado, was forced to flee to Venice.