The Aegean is again open to constant attack from Arab pirates.

A Muslim fleet of fifty-four large galleys manned by Muslim corsairs, led by the renegade Leo of Tripoli, and with the imperial capital of Constantinople as its initial target, sails from Syria, initially driving back the imperial navy under the droungarios Eustathios Argyros.

Eustathios is replaced by Himerios, about whose early life nothing is know.

He is the uncle of Zoe Karbonopsina, the mistress and later wife of Emperor Leo VI the Wise, and his career is the direct result of this relationship.

Initially a protasēkrētis, Himerios in 904 is appointed in command of the imperial fleet.

Himerios does not have to fight, however, as the Arabs withdraw on their own.

The two fleets encounter each other off Thasos, but the imperial navy chooses not to give battle.

As a result, the Arabs are able to turn to Thessalonica, the second city in the empire, totally surprising the imperial navy, which is unable to react in time.

The city walls, especially towards the sea, are in disrepair, while the city's two commanders issue conflicting orders.

After a short siege, the Saracens are able to storm the seaward walls, overcome the Thessalonians' resistance on July 29 and take the city.

The sacking continues for a full week, before the raiders depart for their bases in the Levant, having freed four thousand Muslim prisoners while capturing sixty ships, and gaining a large loot and twenty-two thousand captives, mostly young people.

In the event, most of the captives, including John Kaminiates, who will later chronicle the sack, will be ransomed by the Empire and exchanged for Muslim captives.