The Levant Egypt North Africa Anatolia & Constantinople Border conflicts Sicily and Southern Italy Naval warfare Byzantine reconquest The sack of Thessalonica refers to the capture, and subsequent sack, of the Byzantine city of Thessalonica by the Abbasid Caliphate in the year 904, led by Leo of Tripoli, a privateer and Muslim convert.

[4] The Sack of Thessalonica in 904 by the Abbasid Caliphate's navy was one of the worst disasters to befall the Byzantine Empire during the reign of Leo VI and even in the 10th century.

[5] A Muslim fleet of 54 ships, led by the renegade Leo of Tripoli, who was a recent convert to Islam, set sail from Syria with the imperial capital of Constantinople as its initial target.

The Muslims were deterred from attacking Constantinople, and instead turned to Thessalonica, totally surprising the Byzantines, whose navy was unable to react in time.

An old tradition recounted by John Kaminiates tells that the part of Thessalonica's wall that faces seaward was low, and totally unequipped to deal with any military threat.

At the time of the Muslim sack of the city, this fortification had remained the same, and unimproved, as it was never supposed that it would enter into anyone's head to inflict damage from that quarter.

[5] The Abbasid raiders appeared and after a short siege lasting less than four days, the attackers were able to storm the seaward walls, overcome the Thessalonians' resistance, and take the city on 29 July.

It is said that the Byzantine raid led by General Andronicus Ducas on the region of Germanicea in late 904 was launched to avenge the sack of Thessalonica.