During the ninth century the Saracen Arabs, who had been expelled from the caliphate of Spain, became an increasing threat to the Byzantine empire, particularly after they established themselves on the island of Crete. In 904 a Saracen force led by Leo of Tripoli sailed to the northern Aegean, captured Abydos and prepared to assault Constantinople, but then in a sudden change of plan sailed westward and captured Thessaloniki after a brief siege. The defences of the city had been neglected and the last-minute attempts which were made to improve them had little effect. The victors sacked the city for ten days, then departed taking as many prisoners as they could hold on board their ships. One of these prisoners was Kaminiates, who was later set free in an exchange of prisoners. He subsequently wrote a detailed account of the siege. This book presents the Greek text (as established by Gertrud Böhlig, reprinted by permission of the publisher, W. De Gruyter), together with the first English translation, made by David Frendo, and an introduction and notes by David Frendo and Thanos Fotiou.