Lawrence Mott s study of the War of Sicilian Vespers provides an unprecedented view of the internal organization and operations of a medieval fleet. While the conflict of 1282-1302 between France and the crown of Aragon for control of Sicily had broad geopolitical implications, it was also notable for having been fought primarily at sea. Mott draws on previously overlooked archival materials, most notably the battle fleet accounts of Roger of Lauria discovered in the Archives of the Cathedral of Valencia, in order to produce an account of unprecedented detail, full of original insights into...