Charles of Blois (died September 29 1364), was duke of Brittany, from 1341 to his death.

Charles was the son of Count Guy I of Chatillon and Blois by Margaret of Valois, a sister of king Philip VI of France. He was a devout man, who took piety to the extreme of mortifying his own flesh. It is said that he placed pebbles on his shoes, wore ropes tight with knots near his flesh and confessed every night in fear of sleeping in a state of sin. He was nevertheless an accomplished military leader, who inspired loyalty by his religious fervour.

In 1337 he married Joanna of Dreux, heiress and niece of duke John III. Together, Charles and Joanna fought the House of Montfort in the Breton War of Succession (1341-1364), with the support of the crown of France. Despite his piety, Charles did not hesitate in ordering the massacre of 2000 civilians after the siege of Quimper. After initial successes, Charles was taken prisoner by the English in 1346. He was released nine years afterwards against a ransom of about half a million ecús, and resumed the war against the Montforts.

Charles died in the battle of Auray which determined the end of the war and the victory of the Montforts. He was canonized as saint for his devoutness to religion, but the process was made null by Pope Gregory IX by request of Duke John V of Brittany.

See also

• Dukes of Brittany family tree