It is surprising that so little study should have been devoted to the navy of the later Empire. Since new information has now become available, it would seem a favourable opportunity to consider afresh the structure of the warships of the imperial fleets. The ancient sources may be divided into three main categories. The first is represented by that invaluable collection of tenth century naval handbooks which have recently been edited by M. Dain. Most important for our present purposes are the Περὶ θαλασσομαχίας of the Emperor Leo VI, which may probably be dated to 905–6, and the anonymous Παρὰ Βασιλείον Πατρικίου καὶ Παρακοιμωμένου (cited ‘Anon PBPP’), which M. Dain dates to the years immediately following the Cretan expedition of 960–1. This latter work was unknown to Torr when writing his Ancient Ships, and M. Dain may be said virtually to have rediscovered it. It is addressed to a certain Basil who was the natural son of Romanus Lecapenus. His bastardy stood him in good stead, and he survived the fall of his father and half-brothers. He seems to have attached himself to the party of Nicephorus Phocas, and organized a ‘fifth column’ which contributed in no small part to the overthrow of Joseph Bringas. His nefarious enterprises were finally ended by Basil II, who relegated him to a monastery. All the tenth-century naval handbooks reflect older traditions, and there seems to have been little essential difference between conditions prevailing under the Amorian and the Macedonian dynasties.