In Greek mythology, the Daughters of Danaus (; ), also Danaids, Danaides or Danaïdes, were the fifty daughters of Danaus. They were to marry the fifty sons of Danaus's twin brother Aegyptus, a mythical king of Egypt. In the most common version of the myth, all but one of them killed their husbands on their wedding night, and are condemned to spend eternity carrying water in a sieve or perforated device. In the classical tradition, they come to represent the futility of a repetitive task that can never be completed (see also Sisyphus).