The reason why the Venetians submitted so tamely to being turned out of Ragusa lies in the general situation of affairs in Dalmatia. In 1148 Venice had formed an alliance with the Emperor Manuel Comnenus against the Normans, whose incursions in the Adriatic constituted a menace for both Powers; but Venetians and Greeks were on the worst of terms, and at the siege of Corfu the Emperor’s name had been grossly insulted. Manuel vowed vengeance on his allies, and sent emissaries to stir up the Dalmatians against Venice. The latter was at war on the mainland with Hungary and in Syria, and therefore found it expedient to ignore the Dalmatian question for the time being. Venetian authority, however, did not cease altogether even at Ragusa, where Venetians continued to be appointed as archbishops. Thus in 1150 or 1151 the dignity was conferred on a certain Domenico of Venice, and in 1153 on another Venetian named Tribuno; the latter in 1155 made formal submission to the Patriarch of Grado, with the consent of the clergy and people of Ragusa.[59] The town continued, in fact, to be regarded as one of those under Venetian protection, or, at least, as friendly to the Republic of the lagoons. In 1169 Manuel Comnenus determined to conquer Dalmatia, and even Italy. He sent a squadron up the Adriatic to molest Venetian shipping, and encouraged corsairs to do the same. The Imperial fleet occupied the towns protected by Venice, treating them as conquered territory. Ragusa too was occupied, and was doubtless not unwilling to get rid of all Venetian authority; the Imperial standard was raised on a tower expressly built for the purpose. On March 7, 1171, the Emperor had all the Venetians at Constantinople arrested and their property seized. Venice immediately declared war, and, in spite of the scarcity of men and money, a fleet of one hundred and twenty ships, to which ten Dalmatian galleys were added, was fitted out in a hundred days.[60] It set sail in September under the command of the Doge Vitale Michiel, and most of the Dalmatian towns willingly returned to Venetian suzerainty.[61] Ragusa too surrendered, though not without resistance, and the event is thus described in the _Cronaca Altinate_:[62]—