Aegyptus was the twin brother of king Danaos of Argos. He became the king of
Egypt and Arabia.
From his father's side descended from Poseidon, while from his mother's side from the River Nile.
King Vilos, who reigned in the African countries gave Arabia to Aegyptus and Libya to Danaos. Aegyptus conquer the country of Melampus "those who have black feet", and called her after his name Egypt.
Aegyptus had fifty sons by different women while his brother Danaos had fifty daughters, the Danaides. The two brothers had a quarrel and eventually Danaos fled in Argolis. The sons of Aegyptus went to Argolis to meet the king and asked his daughters in marriage.
Danaos accepted their proposal, but the wedding night he put his daughters to kill all the suitors. The only son of Aegyptus that was spared was Lygkefs, because one of the Danaides, Ypermistra, fell in love with him and she smuggled him out..