sentences:  Leo and Damian would frequently co-operate in the next decade in their attacks on the Byzantine Empire.In the summer of 904, Leo was at the head of a major Abbasid naval expedition of 54 vessels from the Syrian and Egyptian fleets, whose initial target reportedly was Constantinople itself.The Arab fleet penetrated the Dardanelles and sacked Abydos, as the Byzantine navy under the "droungarios" Eustathios Argyros was reluctant to confront them.