According to a Hellenistic astral myth, the Cyclopes were the builders of the first altar. The myth was a catasterism, which explained how the constellation the Altar (Ara) came to be in the heavens. According to the myth, the Cyclopes built an altar upon which Zeus and the other gods swore alliance before their war with the Titans. After their victory, "the gods placed the altar in the sky in commemoration", and thus began the practice, according to the myth, of men swearing oaths upon altars "as a guarantee of their good faith".