How a medieval trade war between Venice and Genoa reshaped the Ottoman Empire
The War of the Straits was a brutal maritime struggle for control of Black Sea trade routes. Beyond the rivalry between two Italian republics, the conflict forced the Genoese into a fateful alliance with the Ottoman Sultan, providing the naval transport that enabled the Ottomans to expand into Europe.
Fought between 1350 and 1355, the War of the Straits was the third major conflict between Venice and Genoa. Both republics were desperate for access to the Black Sea, a vital source of grain for their growing populations and a gateway to Asian trade highways. Tensions escalated as Genoa established colonies like Caffa and Pera, eventually attempting to monopolize passage through the Bosporus. The rivalry was further complicated by the decline of the Byzantine Empire, which struggled to maintain authority as these Italian merchant states turned its capital into a chessboard for their own commercial ambitions.
The war reached a turning point in 1351 when the Genoese, seeking to protect their interests, formed an alliance with the Ottoman Sultan Orhan. In exchange for tribute, Orhan provided archers to defend the Genoese colony of Pera and support their fleet. This partnership proved historically transformative: Genoese ships facilitated the Ottoman crossing of the Bosporus, marking the beginning of Ottoman expansion into Europe—a trajectory that would culminate in the fall of Constantinople in 1453.
By 1352, the conflict had expanded into a pan-Mediterranean struggle involving the Crown of Aragon and the Byzantine Empire. Despite a nominal Genoese victory at the Battle of the Bosporus, both sides were left exhausted by the financial strain and the devastating impact of the Black Death, which had decimated their populations since 1348. The war eventually saw Genoa submit to the rule of Giovanni Visconti of Milan in 1353, as the republic sought a foreign prince to finance its dwindling military efforts. The conflict concluded with shifting alliances and territorial losses, leaving a legacy of geopolitical realignment that permanently altered the Mediterranean world.
Source: War of the Straits
