 Sometime in 1316, John III, Duke of Brittany adopted the plain ermine as the arms of the Duchy of Brittany.At the death of John III in 1341, the succession to the duchy was contested by the duke's niece, Joan of Penthièvre, daughter of his full-brother, and John of Montfort, the duke's younger half-brother.Traditionally, females had been able to succeed as duchesses, but this practice was not consistent with most apanages granted by the French crown, which usually preferred male-only succession.