Stephanos of Byzantium - Ethnika
Darieion: a city of Phrygia. The ethnic, by the rule applied to Phrygian names, with the loss of one syllable, is Dareus—just as from Kotiaion comes Kotiaeus; or, by the rule exemplified by Roiteion and Sigeion, Dareieus.
Stephanos excerpt (left) is aligned with matched Herodian passages (right). Colors indicate corresponding overlap spans.