The Battle at the Bosporus

After the battle near Constantinople in 921, Tsar Simeon concluded a secret treaty with the Egyptian caliph al-Mahdi, seeking an alliance to capture the city. The Byzantines discovered their plans, however, and they failed. Nevertheless, Simeon campaigned against Constantinople again, winning successive victories and reaching its walls once more. These operations led to a battle at the Bosporus between Simeon and Emperor Romanos I Lekapenos on 9 September 923.

The battle resulted in a peace treaty. Despite this and his previous failure, Simeon continued trying to capture Constantinople for the rest of his life.