Peace of Venice

The Treaty or Peace of Venice, 1177, was a peace treaty between the papacy and its allies, the north Italian city-states of the Lombard League, and Frederick I, Holy Roman Emperor. The Norman Kingdom of Sicily also took part in negotiations and the treaty thereby determined the political course of all Italy for the next several years.

The treaty followed on the heels of the Battle of Legnano of 29 May 1176, a defeat for Frederick Barbarossa. Frederick quickly thereafter sent envoys to Pope Alexander III at Anagni, asking for an end to the schism between him and Frederick's antipope, Callixtus III. After a preliminary agreement was reached, a conference was scheduled for July 1177. Frederick spent some time in the interim interfering in Venetian rivalries in hopes of securing a pro-Imperial group in power at the time of the confrontation.

On 24 July, the pope from the Basilica di San Marco sent a delegation of cardinals to the emperor in the Lido, at the mouth of the Venetian Lagoon. The emperor formally acknowledged Alexander as pope and abandoned his own antipope; the cardinals formally lifted the excommunication that had hitherto been placed upon him. Sebastian Ziani, the doge of Venice, and Ulrich II von Treven, the patriarch of Aquileia, then escorted the emperor into Venice itself. The delegates of the king of Sicily were Romuald, Archbishop of Salerno, a chronicler of his time who left us a great eyewitness account of the whole scene, and Count Roger of Andria.

...
Wikipedia