A tetrarch is a Greek term that strictly identifies one of four governors of a divided province. The Romans used the term for one level of military commander. The term is thus used for any subordinate or dependent prince, or for a petty sovereign. Herod the tetrarch had the title of king (Matt. 14:9).

Herod and Phasael, the sons of Antipater, were the first tetrarchs in Palestine.

See also the Tetrarchy established by Diocletian in 293 CE, under which the Roman Empire was divided among two Augusti and two Caesars.

Other uses

A British light tank of WW2