 According to pseudo-Apollodorus, Erechtheus II had a twin brother named Butes who married Erechtheus' daughter Chthonia, the "earth-born".Erechtheus and Butes divided the royal power possessed by Pandion, Erechtheus taking the physical rule but Butes taking the priesthood of Athena and Poseidon, this right being passed on to his descendants.This late origin myth or "aition" justified and validated the descent of the hereditary priesthood of the Boutidai family.