Charles of Blois was a French nobleman born in 1319, known for his role in the Brittany War of Succession. He was the son of Guy de Blois and Margaret of Brittany, which connected him to the ducal family of Brittany. Charles became a prominent figure in the conflict over the Breton throne, supporting the claim of his wife, Joan of Penthièvre. His military efforts included several battles against his rival, John of Montfort, but he was ultimately captured and killed in 1364, marking a significant moment in Breton history.