A phylarch (Greek: φύλαρχος, Latin: phylarchus) is a Greek title meaning "ruler of a tribe", from phyle, "tribe" + archein "to rule".
In Classical Athens, a phylarch was the elected commander of the cavalry provided by each of the city's ten tribes.
During the Hellenistic period, the term had its literal meaning as head of a tribe.
It seemed to apply to Arabs who commanded tribes, essentially the equivalent to "sheikh".
[2] In Thomas More's Utopia (1516), leaders of Utopian cities are called phylarchs.