Syennesis

Syennesis was the name, or perhaps the title, of the native kings of Cilicia in southern Anatolia during the period of Achaemenid rule. Herodotus mentions a Syennesis who helped arrange the peace between Lydia and Media in 585 BCE, and Xenophon describes another who supported Cyrus the Younger in 401 BCE. Cilicia's kings kept considerable autonomy until the early 4th century BCE.