Title of a petty ruler, derived from the Greek τετράρχης and denoting a ruler over the fourth part of a realm. Originally it was conferred by Philip of Macedonia upon the governors of the four districts of Macedonia, but by the beginning of the Christian Era it was used of any subordinate ruler in a given region without any indication of a fourfold political division of government. In the latter sense the title is given to Philip, Lysanias, and herod antipas (Lk 3.1–2, 19; 9.7; Mt 14.1; Acts 13.1). Philip and Antipas were members of the Herodian dynasty, but neither enjoyed the broad powers of Herod the Great. They had to be content with the lesser powers and title of tetrarchs.
Bibliography: Encyclopedic Dictionary of the Bible, translated and adapted by l. hartman (New York, 1963) 2416.
"Tetrarch." New Catholic Encyclopedia. . Encyclopedia.com. (August 16, 2018). http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/tetrarch-0
"Tetrarch." New Catholic Encyclopedia. . Retrieved August 16, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/tetrarch-0