Deianira

Like many mortal women in Greek mythology, Deianira (also Deianeira) occupied a perilous threshold position between the daylit world of Olympian gods and heroes and the dark chthonic primordial world of primitive earth magic. She was the daughter of Althaea and Oeneus ('wine-man' and thus civilized), the king of Calydon, and the sister of Meleager. Her father betrothed her to the fearsome river god Achelous, horned and bull-like. Now Deianira was no passive blushing princess. 'This Deianira drove a chariot and practised the art of war' noted Apollodorus (Library and Epitome, book i, 8:1) But she wanted nothing to do with her suitor, who was able to take the form of a sepent or a bull. Heracles, the greatest hero of the dawning Olympian world of gods and men, had to defeat the river god to win her as his bride.

Deianira's own struggle with the chthonic forces was not over. Later, a wild centaur named Nessus attempted to kidnap Deianira as he was ferrying her across the river Evenus, but she was rescued by Heracles, who shot the centaur with a poisoned arrow. As he lay dying, Nessus lied to Deianira, telling her that a mixture of the semen that he had dropped on the ground and his heart's blood would always ensure that Heracles would love her forever. Deianira believed his words and kept a little of the potion by her. Heracles fathered illegitimate children all across Greece. When she became uncertain if Heracles would remain true to her in his fashion, Deianira smeared some of the blood on Heracles' famous hide shirt. Heracles' servant, Lichas, brought him the shirt and he put it on. The centaur's toxic blood killed Heracles. In despair, Deianira committed suicide.

Reference

Harry Thurston Peck, Harper's Dictionary of Classical Antiquities, 1898.