stylistic:style_transfer, information:classification, quality:corruption, information:highlighting
Galley slaves

Contrary to the popular image of rowers chained to the oars, conveyed by movies such as Ben Hur, there is no evidence that ancient navies made regular use of condemned criminals or slaves as oarsmen, with the possible exception of Ptolemaic Egypt. Literary evidence indicates that both Greek and Roman navies relied on paid labor or ordinary soldiers to man their galleys. Slaves were put at the oars only in times of crisis. In some cases, these people would be given freedom after the crisis was averted. Roman merchant vessels (usually sailing vessels) were manned by slaves, sometimes even with slaves as ship's master, but this was seldom the case in merchant galleys.

It was only in the early 16th century that galley slaves became commonplace. Both galley fleets and the size of individual vessels increased in size during the early modern period, which required more rowers. The number of benches could not be increased without lengthening hulls beyond their structural limits, and more than three oars per bench was not practicable. The demand for more rowers also meant that the relatively limited number of skilled oarsmen could not keep up with the demand of the larger fleets. It became increasingly common to man galleys with convicts or slaves, which required a simpler method of rowing. The older method of employing professional rowers using the alla sensile method (one oar per rower, with two to three rower sharing the same bench) was gradually phased out in favor of a scaloccio, which required less skill. A single large oar was used for each bench, with several rowers working the oar together. The number of oarsmen per oar rose from three up to five and in some of the largest command galleys, there could be as many as seven to an oar.

All major Mediterranean powers sentenced criminals to galley service, but initially only in time of war. Christian naval powers such as Spain frequently employed Muslim captives and prisoners of war. The Ottoman navy and its North African corsair allies put Christian prisoners to the oars in large numbers, but also mixed with volunteers. Habsburg Spain relied mostly on servile rowers, in great part because its organizational structure was geared toward employing slaves and convicts. Venice was one of few major Mediterranean powers that used almost only free rowers, a result of their reliance on alla sensile rowing which required skilled professional rowers. The Knights of Saint John used slaves extensively, as did the Papal States, Florence, and Genoa. The North African ghazi corsairs relied almost entirely on Christian slaves as rowers.