Jeanne de Clisson was a French pirate whose career spent pillaging the English Channel was largely an act of revenge. Turning against her own country, she sought French ships for the pleasure of killing the men on board. While this was helpful for the British, that was not her goal. She was just bent on making the king and his aristocrats pay.
Jeanne de Clisson was born sometime around 1300 and married just 12 years later to a man 7 years her senior. The marriage lasted more than a decade and produced two children, but her husband died when she was in her twenties. A few years later, she married Olivier II de Clisson, which was the first step to her infamy. The two appear to have been in love and had five children together. They lived a comfortable life, thanks to de Clisson's wealth, until the man was tried for treason, found guilty and hanged.
After her husband was beheaded, Jeanne de Clisson went what we might call a little bit crazy. She sold her husband's land and even prostituted herself to wealthy men, allegedly. When she had enough money, she bought three ships, which were painted black and outfitted with red sails. She was a truly frightening figure in her rage.
Jeanne, also known as the "Lioness of Brittany," sought only French ships, killing all but a few on board, so they could tell her tale in France. When she captured the ship of an aristocrat, she beheaded the man with an ax and tossed the body overboard. Then, in 1356, she was done with her revenge. She moved to England, married Sir Walter Bentley and then died three years later.