The Neorion at the Heptascalon played a key role in the naval engagement of 1351, which took place in the Bosporus, involving Byzantine, Venetian, Spanish, and Genoese fleets. Historical accounts by Cantacuzene and Nicephorus Gregoras provide detailed information about the harbour and its strategic importance during this conflict The Harbour of Kaisarius and Its Origins.
Arrival of the Allied Fleets
The Venetian and Spanish fleets came up from the Aegean Sea to support the Byzantine forces. According to Cantacuzene, the allied ships first anchored off the Princes’ Islands to rest their crews after enduring the hardships of winter. They remained there for three days before setting out for the Neorion at the Heptascalon.
This harbour, also referred to as the Neorion of the Byzantines, was where the Imperial fleet was stationed, ready for action. The allies sailed to the harbour to join the Byzantine navy, which awaited their arrival. This demonstrates that the Neorion was not only a docking point but also a strategic military station for the Byzantine navy.
The Genoese Position
Meanwhile, the Genoese admiral positioned his fleet of seventy ships at Chalcedon (modern Kadıköy) to observe and counter the movements of the allied forces. A strong southern wind made the journey from the Princes’ Islands to the Heptascalon difficult. Despite starting very early in the morning, the Venetian and Spanish ships struggled to reach the harbour, finally arriving late in the afternoon. They narrowly avoided disaster, as the waves threatened to smash them against the boulders used as a breakwater along the city walls Private Istanbul Tour.
The Battle
Once the allies had safely joined the Byzantine fleet at the Neorion, the Byzantine admiral led the combined forces to attack the Genoese ships at Chalcedon. The Genoese, unable to sail against the wind, retreated toward Galata, positioning themselves among the shoals and rocks off Besiktas. This gave them a strong defensive advantage.
The resulting combat was fierce and chaotic, occurring partly on the water and partly on the rocky shore. Both sides fought hard, but as night fell, the battle ended without a clear victory for either side. This engagement highlights the strategic importance of the Neorion as a naval base capable of supporting allied fleets and coordinating large-scale maritime operations.
The Neorion at the Heptascalon was not only a commercial harbour but also a critical military station in the mid-14th century. Its location allowed the Byzantines to control the southern approaches of Constantinople, support allied fleets, and engage enemy forces effectively. The 1351 battle demonstrates how the harbour served both defensive and operational roles, showing the continuing strategic significance of Constantinople’s southern ports, even in the late Byzantine period.
