How a desperate Byzantine emperor tried to bankrupt a Genoese colony with tax cuts
In 1348, the Byzantine Empire was financially crippled and dependent on Genoese merchants for food and trade. Emperor John VI Kantakouzenos attempted a bold economic maneuver to reclaim control of the Bosphorus by slashing tariffs. The resulting naval conflict revealed the empire's tragic inability to defend its own maritime sovereignty.
By the mid-14th century, the Byzantine Empire was a shadow of its former self, struggling to recover from a devastating civil war that lasted from 1341 to 1347. The empire’s economy was heavily constrained by the Treaty of Nymphaeum of 1261, which granted the Genoese colony of Galata—a suburb across the Golden Horn from Constantinople—extensive trade privileges. While the Byzantines collected a mere 30,000 hyperpyra annually from Bosphorus shipping, this represented only thirteen percent of the total customs revenue. The vast majority of wealth flowed directly into Genoese coffers, leaving the imperial treasury empty and the state unable to rebuild its shattered naval forces.
Emperor John VI Kantakouzenos sought to break this stranglehold by undercutting Genoese prices. He secured 50,000 hyperpyra in private loans to construct a new fleet and lowered tariffs in Constantinople to divert merchant traffic away from Galata. The Genoese responded by fortifying their colony in violation of existing treaties and declaring war in August 1348. Despite the emperor's preparations, the newly built Byzantine fleet was completely destroyed by early 1349. The conflict saw the Byzantines retaliate by bombarding Galata with catapults and fire, causing significant destruction to the city's infrastructure.
The war concluded with a peace agreement where the Genoese paid a 100,000 hyperpyra indemnity and vacated illegally occupied lands. However, the core issue remained unresolved: the Genoese retained their control over customs duties. Because the Byzantines failed to expel the Genoese from Galata, they were permanently unable to restore their independent sea power. This forced the empire into a cycle of dependency, relying on either Genoa or Venice for naval support. By 1350, Byzantium aligned with Venice, yet the continued defiance of Galata led to a compromise peace in May 1352, cementing the empire's long-term decline as a maritime power.
