Bosphorus Strait Shipping

Timeline

1. 500–1200Northern entrance of the Bosphorus Strait · Bosphorus StraitThe Byzantine Empire maintained fortresses on both shores of the strait (such as the Bosphorus fortress and a castle on the Asian side), levying tolls on passing ships and enforcing navigation controls. Black Sea grain was shipped through here to Constantinople, forming the maritime lifeline of the imperial capital's food security.
2. 1261–1330Galata (north shore of the Golden Horn) · GalataAfter the 1261 Treaty of Nymphaeum, Genoa established a colony and port facilities at Galata, participating extensively in Black Sea–Mediterranean shipping. Genoese vessels passed through the Bosphorus, transshipping Crimean grain, Caucasian furs, and Eastern goods, creating a maritime pattern of both cooperation and competition with the Byzantine authorities.
3. 1331–1340Full course of the Bosphorus Strait · Bosphorus StraitUnder Andronikos III, after the Ottomans took Bursa they approached the southern shore of the Sea of Marmara, and the safety of strait shipping was threatened from the landward side. The Byzantine fleet and Genoese ships still maintained Black Sea grain transport; the Golden Horn chain defense and the strait fortresses jointly protected the capital's sea lanes. Shipping volume over this decade reflected the deepening dependence of the late Byzantine Empire on international trade.