Byzantine–Genoese War (1348–1349)

The Byzantine–Genoese War (1348–1349) was a conflict between the Byzantine Empire and the Republic of Genoa, primarily centered on control of the Bosporus Strait and associated trade routes in the Black Sea. The war stemmed from long-standing tensions between the two powers, exacerbated by Genoese economic dominance in the region and their control of Galata, a fortified suburb directly across the Golden Horn from Constantinople.

The primary cause was the Genoese manipulation of trade and imposition of unfair tolls on Byzantine merchants utilizing the vital sea lanes. Emperor John VI Kantakouzenos, struggling with internal political turmoil and diminished resources, attempted to reduce Genoese power and secure greater revenue for the Byzantine state. Specifically, he sought to reduce the customs duties levied by the Genoese at Galata, which greatly impacted the Byzantine economy.

Open warfare erupted in 1348 when Byzantine attempts to construct new ships and challenge Genoese naval supremacy were met with a Genoese blockade of Constantinople. Genoese forces launched attacks against Byzantine ships and coastal settlements, disrupting trade and further weakening the already fragile Byzantine economy. The siege of Constantinople by the Genoese threatened to cut off the city's food supply, compounding the existing problems caused by the Black Death.

The Byzantine navy, weakened by years of neglect, was unable to effectively challenge the Genoese fleet. Efforts to enlist the aid of Venice and other maritime powers were largely unsuccessful. The war dragged on for over a year, causing significant damage to both sides.

Ultimately, the war concluded with a Byzantine defeat in 1349. While no formal treaty was signed, the Byzantines were forced to concede to Genoese demands and recognize Genoese dominance in the Black Sea trade. The Genoese retained control of Galata and its strategic advantages, further consolidating their economic and political power in the region. The outcome of the war severely weakened the Byzantine Empire and contributed to its long-term decline, highlighting the Empire's diminished capacity to protect its interests against foreign powers.