How did Venice’s relations with the Byzantine Empire become hostile?

Venice’s relationship with the Byzantine Empire shifted from cooperation to hostility due to a combination of commercial rivalry and cultural friction. While Venice initially gained significant trade privileges under Alexius I Comnenus, their presence in Constantinople became increasingly contentious.1

The hostility grew for several reasons:

• Arrogance and Competition: Venetians antagonized the Byzantines through their perceived arrogance and aggressive behavior, while their superior commercial enterprise created deep resentment.1
• Economic Rivalry: The Byzantine emperor attempted to curb Venetian influence by encouraging competition from merchants in Genoa and Pisa. Venice responded by violently destroying their rivals' establishments.1
• Political Crackdowns: In 1171, the emperor arrested all Venetian residents in his dominions and confiscated their goods to maintain order, fueling long-term bitterness.1

This mutual hatred eventually culminated in the Fourth Crusade, during which the Venetians, led by Enrico Dandolo, captured and sacked Constantinople in 1204, leading to the partition of Byzantine territory.2