Gulf of Varna

Varna's bay gave a fortified Black Sea port access to the coast of Dobrudja and the wider Ottoman maritime world. The town was already strongly defended when Amadeus of Savoy besieged it in 1366. Ottoman authority became firmly established in the early fifteenth century, and the battle fought nearby in 1444 secured the city's place within the empire.

The sea also brought danger. Cossack raiders attacked Varna in 1605, and a larger seaborne attack in 1651 was repelled. Writing in 1656, Evliya Çelebi described a castle surrounded by a ditch filled from the Black Sea and continually repaired against this threat. In 1786 the engineer Brognard mapped its defences, including strengthened seaward positions and works protecting the bridge over the Provadya River. Russian forces captured the city after a siege in 1828; it returned to Ottoman rule, and fortifications were rebuilt in 1830–1834. The bay's port combined commerce with repeated efforts to secure its waterfront.