After completing his twelve labors, Hercules left Tiryns and visited many places in Greece where he accomplished many heroic tasks by killing many beasts and helping who ever in need.

After wandering for a long time, he remembered his promise to Meleagrus, to married his sister Deianira daughter of Oeneus & Althaea, or of Dionysus & Althaea, or of Dexamenus, son of Oeceus.

So he arrived in Aetolia where between the rivers Achelous and Euenus was the palace of Deianira.
Hercules told her about his descent to the underworld and his promise to her brother, and he asked her to married him. Instead of a reply Deianira started to cry.

Hercules thought that she was crying because of reminding her dead brother.

- Meleagrus will be very pleased when he we will get married, Deianira, said Hercules. I gave him my word, and I intent to keep it.

But Deianira kept crying and said to Hercules.

- Thank you for the honor and for keeping your promise to my dead brother, but...

- What is wrong? asked Hercules, realizing that she hesitated to continue.

- I can't marry you. A god of our area, Achelous, is after me and by taking various forms, snake, bull and half-man half-bull, is threatening me that if I married anyone else but him he will kill me.

- Do you want to marry me? asked Hercules.

- With all my heard, she said. But Achelous is not joking, he will kill me.

- Do not worry, said Hercules. I will face this god and clear this matter and then we can get married without you worrying about him.

Hercules decided to ambush Achelous by the river with his own name. And one day while Deianira was close by, Achelous assumed the likeness of a bull and emerge from the water closing up on her. Hercules rushed on the bull, grab him by the horns, and wrestled for the hand of Deianira.
The fight was not easy but Hercules managed to broke off one of his horns. Achelous humiliated he promised him that he will no longer bother Deianira again. So Hercules and Deianira got married and lived happily for many years together.

One day Hercules and Deianira came to the river Euenus, at which the centaur Nessus sat and ferried passengers across for hire. So Hercules crossed the river by himself, but because the river was deep he entrusted Deianira to Nessus to carry over. But Nessus intentions where not noble. When ferrying her across he attempted to violate her and tried to run away with her.

When Hercules heard her he was still in the river, he quickly lower his bow and he shot Nessus with a poison arrow (that it was dipped into Hydras blood) in the heart when he emerged from the river. Being at the point of death, Nessus called Deianira, and with revenge in his mind told her.

- I have regretted for what I did to you... I want before I die to do something good for you. Get some blood that flowed from my wound and sprinkle it on a tunic. Give the tunic to Hercules to wear and he will never leave you for the rest of his life.

Deianira believed him and by the time Hercules came close to her the love-charm was ready and she never said anything to Hercules about it.