Ceryx

In Greek mythology, Ceryx /ˈsɪrɪks/ (Ancient Greek: Κῆρυξ, Kērux, literally "herald") was a son of Hermes and either Pandrosus or Agraulus. He was, like his father, a messenger.

According to Pausanias, he was the youngest son of Eumolpus, one of the first priests of Demeter at Eleusis and a founder of the Eleusinian Mysteries.

He founded the two families of high priests in Eleusis: the Kerykes (or Kerukes, a family of priests in Athens) and the Eumolpidae.

In Homer’s time, the kēryx were a profession of trusted attendants or retainers of a chieftain. The role of kērykes expanded, however, to include acting as inviolable messengers between states, even in time of war, proclaiming meetings of the council, popular assembly, or court of law, reciting there the formulas of prayer, and summoning persons to attend. Hermes, himself the kēryx of the gods, was their patron and carried the caduceus, the herald’s staff.

...
Wikipedia