The son of king Belus of Egypt, according to legend Danaus and his brother Aegyptus had 100 children, Danaus 50 girls (the Danaides, "daughters of Danaus" ) and Aegyptus 50 boys.
When all the children had grown into adulthood Aegyptus demanded that all his sons should marry the daughters of Danaus, refusing such a request, Danaus and his daughters fled to the Greek city of Argos, in the northeastern Peloponnese. Aegyptus and his 50 sons pursued them in a hostile manner, and when they arrived in Argos they were in a frenzied mood. Danaus, not wanting them to harm the Argives, consented to the mass wedding, but in reality, hateful of the whole idea.

On the day of the wedding Danaus spoke to each of his daughters, and instructed them all to kill whoever they took for their husband, the plan was to murder them in the wedding bed. All but one successfully killed the cousin they married. The exception was Hypermnestra, which when translated can mean "special intent" or "excessive wooing". The reason she gave for sparing Lynceus' life, and also helping him escape, was that he left her virginity untouched; she loved and respected him for this. Danaus was angered when he learned of his daughters disobedience, so much that he threw her to the mercy of the Argive law courts, but she was acquitted. Some versions say Aphrodite the love goddess intervened.

Danaus had an ingenious way of marrying off the rest of his daughters, by getting the suitors to run the length of a race-course, his daughters standing at the finishing line, each were chosen by the order in which the suitors finished the race.

Lynceus, the husband of Hypermnestra returned to Argos and killed Danaus, as revenge for the deaths of his brothers. Later Lynceus and Hypermnestra ruled Argos and lay the foundation to the dynasty of Argive kings. The descendants of the Danaides were known as the "Danaans" (Danai) in Homer's epic poems, the term simply means "Greeks" or the Greek nation as a whole. The myth of Danaus is probably a reflection of the contact between Egypt and Mycenaean. Greeks (circa 1600-1200 BC and a possible Egyptian origin for the Danaans.

In one version of this legend the 49 daughters, who were guilty of killing their husbands, and for their outrage to the marriage bed, were punished in the underworld after they had died. Their punishment was to continually fetch water, but the jars were full of holes, so no sooner had they filled the jar the water would leak out. (or in some versions the containers were sieves).