The Conspiracy of Sifis Vlastos () was a fifteenth-century planned rebellion against the Republic of Venice in the overseas colony of Crete, named after its chief instigator. Vlastos and his collaborators were betrayed to the Venetian authorities, who swiftly arrested and executed them in 1454. A smaller, follow-on plan for an intended uprising against Venice was dismantled in 1462. Background Crete under Venice Crete had been under Venetian rule since 1211, having been sold to Venice by Boniface of Montferrat at the time of the Fourth Crusade. Owing to its central location along the trade routes, its size and its products, Crete had a strategic importance for the Venetian rule in the Eastern Mediterranean. Occupied Crete was divided into fiefs and a colony known as the Kingdom of Candia () had been established, having as capital the city of Candia (present-day Heraklion). The land was distributed to Venetian colonists (both nobles and citizens) on the condition that they paid taxes, crewed Venetian warships and defended the possession in the name of Venice. Crete was governed by a Venetian noble elected by the Great Council of Venice, who bore the title of Duke of Candia and was assisted by two Councillors. Large cities were governed by Rectors who served under the Duke. Venetians ruled Crete primarily for their own interest, driving Cretans to forced labour or conscripting them for the wars of the Republic. During the five centuries of Venetian rule, Crete saw many rebellions by the native Cretan population against Venice. Unification of the Catholic and Orthodox churches In the early fifteenth century, the Byzantine Empire was on the verge of collapse due to the expansion of the Ottoman Turkish empire. Hoping to receive military assistance from the West, the Byzantine emperor John VIII Palaiologos was eager to form an alliance with the Latin Church. Hence, he arranged with Pope Eugene IV to hold discussions about reunion at the Council of Ferrara-Florence. After long negotiations and political pressure by the Byzantine Emperor, all Eastern bishopric representatives except Mark of Ephesus accepted Western doctrines such as Papal supremacy, Filioque and Purgatory, and in July 1439 signed a proclamation declaring the reunification of Latin and Eastern churches. However, upon returning to their home cities, Eastern bishops found that their agreement with the West was rejected by the populace and the vast majority of the low clergy. As a result, the union signed