Tetrarch Properly governor of the fourth part of a larger province and kingdom, i.e. a tetrarchy. The title "king" is applied by courtesy, not right, to Herod "the tetrarch" (Luke 3:1; Mark 6:14). I (See tid=1654) As Archelaus was "ethnarch" over half of Herod the Great's whole kingdom, so Philip and Antipus had divided between them the remaining half, and were each "tetrarch" over the fourth; Herod over Galilee; Philip over Ituraea and Trachonitis; Lysanias over Abilene. Caligula annexed the three tetrarchies to the kingdom of Herod Agrippa I, whom he honoured with the title "king" (Acts 12).