The probability is that no such method of working was ever generally employed, and that the belief in the existence of old-world navies made up of ships with tier on tier of oars on either side is the outcome of a misunderstanding as to the meaning of a word. _Triêres_ and _trireme_ seems at first glance to mean triple-oared, in the sense of the oars being triplicated; but there are strong arguments for the view that it was not the oars but the oarsmen, who were arranged in "threes." If this view is correct, the ancient warship was a galley with a single row of long oars on either side, and three men pulling together each heavy oar. We know that in the old navies of the Papal States and the Republics of Venice and Genoa in the Middle Ages and the days of the Renaissance, and in the royal galleys of the old French monarchy, there were no ships with superposed banks of oars, but there were galleys known as "triremes," "quadriremes," and "pentaremes," driven by long oars each worked by three, four, or five rowers. It is at least very likely that this was the method adopted in the warships of still earlier times. A trireme of the days of the Persian War with fifty or sixty oars would thus have a crew of 150 or 180 rowers. Add to this some fifty or sixty fighting men and we have a total crew of over two hundred. In the Persian navies the rowers were mostly slaves, like the galley slaves of later times. They were chained to their oars, and kept in order or roused to exertion by the whip of their taskmasters. To train them to work together effectively required a long apprenticeship, and in rough water their work was especially difficult. To miss the regular time of the stroke was dangerous, for the long oars projecting far inboard would knock down and injure the nearest rowers, unless all swung accurately together. The flat-bottomed galleys rolled badly in a heavy sea, and in rough weather rowing was fatiguing and even perilous work. Some two hundred men in a small ship meant crowded quarters, and lack of room everywhere except on the fighting deck. But as the fleets hugged the shore, and generally lay up for the night, the crews could mostly land to cook, eat, and sleep. In the Persian ships belonging to many nations, and some of them to the Greek cities of Asia, Xerxes took the precaution of having at least thirty picked Persian warriors in each crew. Their presence was intended to secure the fidelity of the rest.