Gongylos, from Eretria in Euboea, was a 5th-century BCE Greek statesman who served as an intermediary between the Spartans and Xerxes I of the Achaemenid Empire, and was a supporter of the latter.
Likely portrait of one of the Gongylid rulers, from a 5th century coin of Pergamon.
Possible coinage of Gongylos, with Apollo on the obverse, and Gongylos wearing the Persian cap on the reverse, as ruler of Pergamon for the Achaemenid Empire. Pergamon, Mysia, circa 450 BCE. The name of the city ΠΕΡΓ ("PERG"), appears for the first time on this coinage, the first evidence for the name of the city.
Prokles was a descendant of the exiled Spartan king Demaratus, and ruler of Pergamon in Asia Minor under the Achaemenid Empire. He was a brother of Eurysthenes, with whom he was a joint ruler.
Gongylos
…Minor, as well as from the descendants of Demaratos, a Spartan exile who also had become a satrap for the Achaemenids, in the person of his descendant Prokles. It is thought that the Greek dynasts of Pergamon were punished following the Peace of Antalcidas in 386 BCE for their support of the Greeks against…
Portrait of Prokles, from his coinage, circa 400 BC
Coin of Prokles, brother and co-ruler of Eurysthenes, as Dynast of Teuthrania and Halisarna, circa 400-399 BC. Obv: Head of Apollo. Rev: Portrait of Prokles wearing the Persian cap. Letters ΤΕΥ ("TEU", for Teuthrania). Teuthrania, Mysia. Laureate head of Apollo left / Head of Prokles right, wearing Persian headdress.