a prince who holds and governs a fourth part of a kingdom. Such originally was the import of the title tetrarch; but it was afterwards applied to any petty king or sovereign; and became synonymous with ethnarch, as appears from the following considerations: 1. That Pliny makes mention of six tetrarchies within the city of Decapolis. 2. That Herod's kingdom was only divided into three parts, which yet were called tetrarchies, and the sovereigns thereof, Luke iii. 1. tetrarches. 3. Josephus tells us, that, after the battle of Philippi, Antony, going into Syria, constituted Herod tetrarch; and on medals the same Herod is called ethnarch.