He supported Frederick I, Holy Roman Emperor, (1122–1190) in his unsuccessful struggle for supremacy over the northern Italian states and the papacy.

Three years later Pope John XIX declared that Grado was just a parish of Aquileia, which was metropolitan of all Venice.

[5] In 1155 Pope Adrian IV granted the patriarch of Grado jurisdiction over parts of the coast of Dalmatia, causing renewed tension.

[4] In 1162, while Venice was involved in a war with Padua and Ferrara, Patriarch Ulrich of Aquileia attacked Grado.

[7] Ulrich II continued to support the rival popes of the emperor until late in the 1160s, when he transferred his allegiance to Alexander III.

[9] On 24 July 1177 Sebastiano Ziani, the doge of Venice, and Ulrich II von Treven escorted the emperor from San Nicolò al Lido into Venice, where he met the pope and was reconciled in an emotional public scene in front of St Mark's Basilica.

[9] The Treaty of Venice, ratified on 1 August 1177, temporarily resolved the differences between the emperor, the papacy and the north Italian city-states of the Lombard League.

[9] Ulrich II, as a confidant of both the pope and the emperor, had been instrumental in reconciling the two and healing the division in the church.

The Patriarchate of Aquileia ended formally in 1751 with the 6 July bull Injunctio Nobis by pope Benedict XIV.