Roman civil wars
The exact arrangement of the hexareme's oars is unclear. If it evolved naturally from the earlier designs, it would be a trireme with two rowers per oar; the less likely alternative is that it had two levels with three oarsmen at each. Reports about "sixes" used during the 1st-century BC Roman civil wars indicate that they were of a similar height to the quinqueremes, and record the presence of towers on the deck of a "six" serving as flagship to Marcus Junius Brutus.