Tags: Mythological Figure.
In Greek mythology Oncius (Ὅγκιος Onkios) or Oncus (Ὅγκος Onkos) was a son of Apollo and a ruler over Oncium (Onkeion) a region of Arcadia adjacent to Thelpusa as well as eponym of a city Oncae. He owned a herd of horses in which Demeter tried to hide from Poseidon’s advances changing herself into a mare. Poseidon did mate with her in the shape of a stallion which resulted in the birth of the fantastic horse Arion.