Archon eponymos

In ancient Greece the chief magistrate in various Greek city states was called eponymous archon (ἐπώνυμος ἄρχων, epōnymos archōn). Archon (ἄρχων, pl. ἄρχοντες, archontes) means "ruler" or "lord," frequently used as the title of a specific public office, while "eponymous" means that he gave his name to the year in which he held office, much like the Roman dating by consular years.

In Classical Athens, a system of nine concurrent archons evolved, led by three respective remits over the civic, military, and religious affairs of the state: the three office holders were known as the eponymous archon, the polemarch (πολέμαρχος, "war ruler"), and the archon basileus (ἄρχων βασιλεύς, "king ruler"). The six others were the thesmothetai, judicial officers. Originally these offices were filled from the wealthier classes by elections every ten years. During this period the eponymous archon was the chief magistrate, the polemarch was the head of the armed forces, and the archon basileus was responsible for some civic religious arrangements, and for the supervision of some major trials in the law courts. After 683 BC the offices were held for only a single year, and the year was named after the eponymous archon.

The archon was the chief magistrate in many Greek cities, but in Athens there was a council of archons which exerted a form of executive government. From the late 8th century BC there were three archons: the archon eponymos, the polemarchos (replaced in 501 BC by ten strategoi), and the archon basileus (the ceremonial vestige of the Athenian monarchy). These positions were filled from the aristocracy (the Eupatridae) by elections every ten years. During this period Archon Eponymous was the chief magistrate, the Polemarch was the head of the armed forces, and the Archon Basileus was responsible for the civic religious arrangements.

...
Wikipedia