Charles of Blois (Blois, 1319 ? September 29, 1364), claimed the title duke of Brittany, from 1341 to his death.
Charles is the son of Guy I of Blois-Châtillon, count of 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 placedpebbles in 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.
On June 4, 1337 in Paris, he married Joanna the Lame, 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 1347. 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 devotion to religion, but the process was made null by Pope Gregory XI by request of Duke John V of Brittany. Subsequently, in 1904, he was beatified.
By his marriage to Joanna, he had five children:
John I of Blois-Châtillon (1340?1404)
Henry (d. 1400)
Marie (1345-1404), Lady of Guise, married in 1360 Louis I of Naples
Marguerite, married in 1351 Charles de la Cerda (d. 1354)
1373: King Edward III's praecipe directed John Legge and William de Weston, to receive from Roger de Beauchamp, Constable of the castle of Devizes, the two sons of Charles de Blois, and to deliver them to Robert de Morton, Lieutenant of Collard de Aubrichecourt, Constable of Nottingham Castle, there to remain as hostages , till the pretensions to the duchy of Britany should be cleared.