Deioces

Deioces, Diako, Diaco, Deyaco, Diyako or Deiokes (Greek Δηιόκης) was, according to Herodotus, the first king of the Medes although this is contested. In the late 8th century BC there was a Daiukku or Dayukku who was a Mannaean provincial governor. Perhaps Herodotus used the name in error.

Deioces in Herodotus

Herodotus (I: 96ff) says that Deioces (Deyaco), father of Phraortes, was "a man of great ability and ambitious for power" in a time when there was no government in the region; people in his own and other villages chose him to arbitrate disputes, and eventually selected him as their king: "Let us appoint one of our number to rule us so that we can get on with our work under orderly government, and not lose our homes altogether in the present chaos." They built him first a palace and then a capital, Ecbatana (modern Hamadan). He established a strict protocol of seclusion and deference as well as a nationwide network of spies, administered justice, and ruled for fifty-three years; his son and successor was Phraortes, father of Cyaxares, who overthrew the Assyrian Empire and established the power of Media.