In Greek mythology, Hippocoön (Ancient Greek: Ἱπποκόων) was a king of Sparta. He was a son of King Oebalus and Bateia, and a brother (or half-brother) of Tyndareus and Icarius. After their father's death he and his many sons seized the throne and drove his brothers into exile. He was eventually killed by Heracles, who restored Tyndareus to power and slew Hippocoön's sons in revenge.
Adapted from Wikipedia, "Hippocoon (king of Sparta)" · CC BY-SA 4.0
I.Family
Hippocoön was the son of the Spartan king Oebalus and Bateia. His siblings were Tyndareus and Icarius, though the sources differ over whether they were full brothers or half-brothers.
He fathered numerous sons. Among those named are Dorycleus, Scaeus, Enarophorus, Euteiches, Bucolus, Lycaethus, Tebrus, Eurytus, Hippothous, Hippocorystes, Alcinous, Alcimus, Dorceus, Sebrus, Eumedes, Enaesimus, Alcon, and Leucippus. The last three of these were said to have taken part in the Calydonian boar hunt. Diodorus Siculus reports that Hippocoön had twenty sons in all, without naming each of them individually.
II.Mythology
After the death of their father, Tyndareus at first became king of Sparta. Hippocoön, however, with the support of his many sons, overthrew his brother, took the throne for himself, and expelled his brothers from the kingdom.
III.Conflict with Heracles
Later, Hippocoön refused to purify Heracles after the death of Iphitus. This refusal angered Heracles, who made war upon Hippocoön, defeated and killed him, and restored Tyndareus to power.
Heracles also slew all of Hippocoön's sons, in revenge for the death of Oeonus, son of Licymnius, who had been killed by Hippocoön's sons. In this campaign Heracles was supported by Cepheus, king of Tegea in Arcadia, and his sons, as well as by Iphicles, Heracles's brother; many of these allies fell in the fighting. According to Diodorus Siculus, three of Cepheus's sons survived.