The trireme was developed during the early fifth century B.C. in Greece probably from designs the Phoenicians were using. The “tri” in trireme refers to the three types of oarsmen in the ship - thalamites, zygites, and thranites. Why these types existed and how they functioned is a mystery.
There are four principle ways to configure oarsmen in a trireme: in a single line on each side of the boat; vertically, one group above another; assigning multiple rowers per oar; or placing rowers next to each other on a common bench. The following discussion will attempt to determine which of these options was in use.