Venetian-Byzantine War of 1170-77

Constantinople’s fleet checks initial Venetian moves in the Aegean from 1170.

A truce is concluded in 1177; a peace treaty will follow in 1183.

The personal relationships of Emperor Manuel with the crusaders and with other Westerners remains cordial, but his policies have antagonized the German Empire, the papacy, the Normans of southern Italy, and, not least, the Venetians, with whom mutual dislike has ripened into hatred.

The emperor encourages merchants from the Italian republics of Genoa and Pisa to compete in imperial markets.

His effort to revive imperial prestige in Italy and the Balkans, and his treaties with Genoa in 1169 and Pisa in 1170, rouse the suspicions of Venice: the Venetians respond by destroying the establishments of their rivals, sparking a seven-year war with Constantinople.

The Greeks, resentful of the increasing presence in Constantinople of Venetian merchants and the privileges accorded them following the two Crusades, entreat the emperor to act against them.

Following an anti-Latin demonstration in Constantinople in 1171, the emperor, to maintain order in his dominions, and egged on by Genoa, Pisa, and other of the Venetians' trading rivals, in a single day arrests all Venetian residents in Constantinople and the provinces and briefly confiscates their goods.

Emperor Manuel, in prosecuting the war with Venice that began in 1170, seizes Venetian outposts in the Aegean: …

…other Venetian holdings in the Adriatic fall to Hungary's Stephen III, who advances with his troops along the Dalmatian coast.

The Venetians, who break relations with Constantinople in 1171, will not forget this episode.

They, too, begin to think in terms of putting Constantinople under Western control as the only means of securing their interest in Greek trade.

Venice, with aid from the Norman kingdom of Sicily in 1172, seizes Ragusa and …

…sacks the imperial possessions of Chios and …

…Lesbos.

The Venetian doge, in financing an expedition to retake the Dalmatian coastal cities of Zara (Zadar) and Ragusa (Dubrovnik) and the Aegean seaport of Negropont (Chalcis), issues the first government bonds.