The earliest source for stories about Phaedra would be the mythological cycle surrounding Theseus and the foundation of Athens. Phaedra was the wife of Theseus (one of a series actually -- he later marries the Amazon Queen Hipppolyta) and daughter of King Minos.

The most influential literary portraits of her have been:
   
 Hippolytus by Euripides: Classical Greek tragedy

Phaedra by Seneca the Younger. A Latin tragedy based on the Greek of Euripides but considerably more melodramatic.

Phèdre by Jean Racine: 1677. A classical French drama based on Seneca's tragedy. In this, Racine emphasizes issues of Christian morality in the face of various temptations.