Siege of Thessalonica

The siege of Thessalonica between 1422 and 1430 saw the Ottoman Empire under Sultan Murad II capture the city of Thessalonica, which remained in Ottoman hands for the next five centuries, until it became part of the Kingdom of Greece in 1912.

Thessalonica had already been under Ottoman control from 1387 to 1403 before returning to Byzantine rule in the aftermath of the Battle of Ankara. In 1422, after the Byzantines supported Mustafa Çelebi as a rival pretender against him, Murad attacked Thessalonica. Unable to provide manpower or resources for the city's defense, its ruler, Andronikos Palaiologos, handed it over to the Republic of Venice in September 1423. The Venetians attempted to persuade the Sultan to recognize their possession, but failed as Murad considered the city his by right and the Venetians to be interlopers. This impasse led to an Ottoman blockade of Thessalonica, which occasionally flared up with direct attacks on the city. At the same time, the conflict was mostly fought as a series of raids by both sides against the other's territories in the Balkans and the Aegean Islands. The Venetians repeatedly tried to apply pressure by blocking the passage of the Dardanelles at Gallipoli, with little success.

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