Hippolyta first appears in myth when she is kidnapped by Theseus, who was either accompanying Heracles on his quest against the Amazons, or he was just bored and looking for something to do. (It is generally accepted that Theseus acted on his own.) When Theseus first arrived at the land of the Amazons they expected no malice, and so Hippolyta came to his ship bearing gifts. Once she was aboard Theseus set sail for Athens, claiming the queen as his bride.
Theseus' brazen act sparked an Amazonomachy, a great battle between the Athenians and Amazons. Most of the great heroes in ancient Greece fought in an Amazonomachy, and Theseus could not be left out. The Amazons made camp in Attica on a hill that has been described as "bare and rocky", the Areios Pagos 1. It would become the most famous court of law of ancient times. The apostle Paul gave one of his best known speeches on the Areios Pagos.
Even though Hippolyta bore a son to Theseus, who was called Hippolytus, she was cast off when Theseus had eyes for Phaedra. Scorned, Hippolyta went back to the Amazons, while Hippolytus had problems of his own with his new stepmother. (Some sources paint Theseus in a more favorable light, saying that Hippolyta was dead before he and Phaedra were wed.)
Hippolyta also appears in the myth of Heracles. It was her girdle that Heracles was sent to retrieve for Admeta, the daughter of king Eurystheus. The girdle was a waist belt from Ares that signified her authority as queen of the Amazons.
When Heracles landed the Amazons received him warmly and Hippolyta came to his ship to greet him. Upon hearing his request, she agreed to let him take the girdle. Hera, however, was not pleased, as was often the case with Heracles. To stop him, Hera came down to the Amazons disguised as one of their own and ran through the land, crying that Heracles meant to kidnap their queen. Probably remembering all too well what Theseus had done, the Amazons charged toward the ship to save Hippolyta. Fearing that Hippolyta had betrayed him, Heracles hastily killed her, ripped the girdle from her lifeless body, and set sail, narrowly escaping the raging warriors.
An alternate story of Hippolyta's death is a direct result of Theseus' marriage to Phaedra. With an army of Amazons behind her, Hippolyta returned to Athens and stormed into the wedding of Theseus and Phaedra. She declared that anyone partaking in the festivities would perish, but in the melee that ensued she was killed, either accidentally by her companion Penthesileia or by Theseus' men.
Since Hippolyta obviously could not die twice (there are no stories of divine intervention or resurrection) there exists a strange paradox in Hippolyta. Some sources explain away this paradox by saying that Antiopê and Hippolyta are not the same woman, but, rather, are two separate queens of the Amazons, with different names and leading different lives.