Jeanne-Louis de Belleville
1300 - 1359
When her second husband Oliver III de Clisson failed to defend Vannes  against British forces, he fell under suspicion by the French, especially Charles of Blois and so fled to Britain. He was later captured by the French while on vacation in France  or attending a Tourney in French territory  and was hanged  or beheaded  in 1326  or 1343  and his head displayed on the wall of the castle of Boufay .
Jeanne sought revenge. She "sold off every inch of her family's land"  and possibly sold her body to nobels  and lead massacres, including an attack on the Chateau Thébaut . When the land war got too dangerous  she bought the three biggest warships she could find"  and painted them jet black and gave them red sails . From 1337  or 1346  until 1356 she "ruled the waves" with her "the Black Fleet"  a fleet of "the most fabulous ships the world will likely ever know."  She was "known for" killing everyone aboard French ships belonging to King Philip VI she seized (including beheading French aristocrats with an axe), apart from one  or two  or three  (a few ) sailors who were ordered to inform the French king of what she had done. She kept the channel free of French warships and kept the British army supplied until well after Philip's death in 1350. 
In 1356 she married English nobleman Sir Walter Bentley, but later returned to France and died in 1359. 
John III, Duke of Brittany died with no male heirs in 1341, his half brother John IV contested the rights of his niece Joanna of Penthièvre, and her husband, Charles of Blois, to the Duchy of Brittany leading to the Breton War of Succession. Oliver, a supporter of John IV's was captured at a tournament and executed.
French legal records from 1343 do condemn Jeanne as a traitor in her own right and order the confiscation of her lands. There is a record 1345 order by the English court that Jeanne be granted an income from lands King Edward III of England (who had supported the by this time late John III, and his successor John IV) now controlled in Brittany. She is later mentioned in a 1349 truce agreement as a valuable English ally. These sources suggested she may have been involved in martial activities for a period of five months, between Oliver's death and her fleeing to England. In 1349 she married English nobleman Sir Walter Bentley, Edwards' commander and they returned to England where Bentley became responsible for all of Edward's interests in Brittany.
It is not known when she died, but her son Oliver claimed her lands and incomesin 1359 and received them. Oliver later allied himself with the French, gaining back his father's title and lands and becoming Constable of France under Charles VI.
In 1868, French writer Émile Pehant's novel Jean de Belleville was published in France. Writing at the height of the French Romantic Movement, Pehant's novel shares many details with the legend attached to Jeanne.