Byzantine–Venetian treaty of 1277

The agreement was beneficial for both sides: Byzantine emperor Michael VIII Palaiologos kept the Venetians and their fleet from participating in the attempts of Charles of Anjou to organize an anti-Byzantine crusade, while the Venetians were able to retain their access to the Byzantine market, and even augment their trading privileges by gaining direct access to the Black Sea and the right to their own quarters in Constantinople and Thessalonica.

Furthermore, they were able to stop the Byzantine reconquest of Venetian-aligned territories in the Aegean, although the treaty explicitly allowed both sides to continue fighting for control of the island of Euboea (Negroponte).

After the treaty expired, the Venetians allied with Charles of Anjou, but their plans were thwarted by the outbreak of the War of the Sicilian Vespers in 1282, forcing Venice once more to renew the peace with the Byzantines in 1285.

[5][6] With the rise of the ambitious Charles of Anjou in Italy, both Palaiologos and the Venetians became interested in a mutual rapprochement, leading finally to the conclusion of a five-year peace treaty in 1268.

[22] Contarini was careful to avoid terms that might give offense to Palaiologos, omitting the title 'Lord of one-quarter and one-eighth of the Empire of Romania' that his predecessors had claimed since the Fourth Crusade, and limiting himself to the title of 'Doge of Venice, Dalmatia, and Croatia, and lord of the places and islands subject to his Dogate' (Latin: Venecie, Dalmacie et Croacie Dux, dominus terrarum et insularum suo Ducatui subiectarum).

[22][25] Notably, this agreement was not phrased as a treaty between equals, but rather as a chrysobull, a deed of grant, from the Emperor, "desirous of keeping the peace with all Christians", to Venice.

The outbreak of the Vespers had ruined Venetian chances to recover their privileged position, and for the duration of the state of war their trade with the East was interrupted, much to the advantage of the Genoese.

The commissioners, Giberto Dandolo, Marino Gradenigo, and Lorenzo Sagredo, examined 339 claims on 257 incidents, consulting official dispatches by Venetian agents in the Aegean as well as oral evidence from individuals, and issued their report in March 1278.