[3][note 1] It was used in the region even after it fell under the dominion of Rome, and into the early Roman Empire, to refer to rulers of vassal kingdoms who did not rise to the level of kings.
His brother Philip received the north-east of the realm and was styled Tetrarch (circa 'ruler of a quarter'); and Galilee was given to Herod Antipas, who bore the same title.
Consequently, Archelaus' title singled him out as the senior ruler, higher in rank than the tetrarchs and the chief of the Jewish nation; these three sovereignties were in a sense reunited under Herod Agrippa from AD 41 to 44.
[3][note 2] However the definition of the word in terms of the actual jurisdiction and public office of the ethnarch may not be accurately determined.
Although the specific nature of the title is not attested, it is generally accepted that in the 10th–11th centuries, it signified the commanders of the contingent of foreign mercenaries serving in the Byzantine army.
[2] Rather different was the case of minority community ethnarchs, especially within the Islamic Ottoman Empire that were recognized as legitimate entities (millet) and thus allowed to be heard by the government through an officially acknowledged representative, though without political persona.