Byzantine-Venetian Trade Dispute (1130s)

Timeline

1. 1131–1134Constantinople · Byzantine EmpireJohn II began reviewing at court and in the treasury the tax-exempt and port privileges granted to the Venetians by Alexios I in 1082, demanding higher tariffs from Venetian merchants and restricting their warehousing facilities in imperial ports, provoking strong protests from the Venetian Senate.
2. 1135–1138Aegean · AegeanThe Byzantine fleet intercepted and detained some Venetian merchant ships in the Aegean, while Venice responded with armed escorts and port boycotts; trade was nearly suspended, and though diplomatic envoys met frequently, no comprehensive new treaty was reached.
3. 1139–1140Venice · VeniceBy around 1140 both sides still maintained limited trade but a comprehensive treaty remained unresolved; Venice insisted on restoring old privileges while Byzantium demanded reciprocal concessions; the stalemate persisted until Manuel I's reign after John II's death, when it was partly resolved by the 1147-1148 treaty.