Zosimus (1. v. [c. 20] p. 319) mentions these galleys by the name of 'Liburnians', and observes that they were as swift (without explaining the difference between them) as the vessels with fifty oars; but that they were far inferior in speed to the 'triremes', which had been long disused. Yet he reasonably concludes, from the testimony of Polybius, that galleys of a still larger size had been constructed in the Punic wars. Since the establishment of the Roman empire over the Mediterranean, the useless art of building large ships of war had probably been neglected, and at length forgotten.