and rendering it helpless against missile fire and boarding. The four galeai ships uncovered in the Yenikapi excavations, dating to the 10th–11th centuries, are of uniform design and construction, suggesting centralized manufacturing. They have a length of about , and are built of European Black Pine and Oriental plane. Variants By the 10th century, there were three main classes of bireme warships of the general dromon type, as detailed in the inventories for the expeditions sent against the Emirate of Crete in 911 and 949: the [chelandion] ousiakon (), so named because it was manned by an ousia of 108 men; the [chelandion] pamphylon ([χελάνδιον] πάμφυλον), crewed with up to 120–160 men, its name either implying an origin in the region of Pamphylia as a transport ship or its crewing with "picked crews" (from , "all tribes"); and the dromōn proper, crewed by two ousiai. In Constantine VII's De Ceremoniis, the heavy dromōn is said to have an even larger crew of 230 rowers and 70 marines; the naval expert John H. Pryor considers them as supernumerary crews being carried aboard, while Makrypoulias suggests that the extra men correspond to a second rower on each of the upper-bank oars. A smaller, single-bank ship, the monērēs (μονήρης, "single-banked") or galea (γαλέα, from which the term "galley" derives), with c. 60 men as crew, was used for scouting missions but also in the wings of the battle line. Three-banked ("trireme") dromons are described in a 10th-century work dedicated to the parakoimōmenos Basil Lekapenos. However, this treatise, which survives only in fragments, draws heavily upon references on the appearance and construction of a classical Greek trireme, and must therefore be used with care when trying to apply it to the warships of the middle Byzantine period. The existence of trireme vessels is, however, attested in the Fatimid navy in the 11th and 12th centuries, and references made by Leo VI to large Arab ships in the 10th century may also indicate trireme galleys. For cargo transport, the Byzantines usually commandeered ordinary merchantmen as transport ships (phortēgoi) or supply ships (skeuophora). These appear to have been mostly sailing vessels, rather than oared. The Byzantines and Arabs also employed horse-transports (hippagōga), which were either sailing ships or galleys, the latter certainly modified to accommodate the horses. Given that the chelandia appear originally to have been oared horse-transports, this would imply differences in construction between the