Charles, Duke of Brittany

Charles of Blois-Châtillon, nicknamed "the Saint", was Duke of Brittany from 1341 until his death. He claimed the duchy jure uxoris through his wife, Joan, Duchess of Brittany, holding the title against the claims of John of Montfort. The cause of his possible canonization was the subject of a good deal of political maneuvering on the part of his cousin, Charles V of France, who endorsed it, and his rival, John of Montfort, who opposed it. The cause fell dormant after Pope Gregory XI left Avignon in 1376, but was revived in 1894. Charles of Blois was beatified in 1904.