Caenis

Latinized form of Kainis. In Greek mythology, Caenis was a woman who was raped by the god Poseidon. Afterwards, he promised her that he would grant her a single wish. Caenis then made the wish to become a man with the name of Caeneus, so that she would never again have to suffer rape or any other injustices that women often had to face. Poseidon made good on his promise, and she was transformed into the man she wanted to be.

In real life, a notable bearer of this name was Antonia Caenis (died in 74 AD). She was a former slave, who was the long-term mistress of the Roman emperor Vespasian.