Two Athenians, Theseus and Pirithous, thought that since they were both sons of Gods, both should have divine wives; they thus pledged to help each other abduct two daughters of Zeus. Theseus chose Helen, and Pirithous vowed to marry Persephone, the wife of Hades. Theseus took Helen and left her with his mother Aethra or his associate Aphidnus at Aphidnae or Athens. Theseus and Pirithous then traveled to the underworld, the domain of Hades, to kidnap Persephone. Hades pretended to offer them hospitality and set a feast, but, as soon as the pair sat down, snakes coiled around their feet and held them there. Helen's abduction caused an invasion of Athens by Castor and Pollux, who captured Aethra in revenge, and returned their sister to Sparta.