After the
sack of
Constantinople by the
Fourth Crusade and the dissolution of the Byzantine Empire in 1204, the city was up for grabs. In the
partition treaty among the Crusaders, the
Republic of Venice had secured recognition of her claims on the westernmost Byzantine provinces, which were crucial in view of the vital Venetian interests in the
Adriatic Sea. However, the claim had to be quickly enforced, lest others, and chiefly the Venetians' main rivals, the
Genoese, occupy it first. As a result, in the summer of 1205, the Venetian fleet carrying the new
Latin Patriarch of Constantinople to his see, also attacked and captured Durazzo and
Corfu. At Durazzo, the Venetians met little opposition and one of the captains, Marino Vallaresso, was appointed as the new
Duke of Durazzo, a sign of the value the Venetians placed in their new possession. For the same reason they insisted on the appointment of the city's
Roman Catholic archbishop, who replaced the previous
Greek Orthodox prelate, directly by Venice, without the involvement of the
Pope. Although the Venetians had also laid claim to the mainland region of
Epirus, they did not move to establish control there. Consequently, the area came under the rule of a
Byzantine Greek aristocrat,
Michael I Komnenos Doukas, who established his own principality there, the
Despotate of Epirus. Doukas' power grew quickly, and he soon controlled all the mainland between the Venetian Duchy of Durazzo and the
Corinthian Gulf in the south. Unable and unwilling to undertake the effort necessary confront him, the Venetians preferred to conclude a compromise treaty with Doukas in June 1210, which recognized him as ruler of Epirus, but as the nominal vassal of Venice, which had claimed this territory since 1204. This treaty was expedient for Doukas, but did not mean the abandonment of his own designs on Durazzo: in 1213, his forces captured the city, ended the Venetian presence, and restored a Greek Orthodox archbishop to the local see. Soon after, Doukas' forces also took Corfu, and moved to extend his rule over Albania and western
Macedonia, capturing the lordship of
Croia and pushing up to the borders of
Zeta. ==Aftermath==