John III, Duke of Brittany was born in 1286 and became the Duke of Brittany in 1312. He was the son of John II, Duke of Brittany and Beatrice of England. His reign was marked by efforts to strengthen the duchy's independence and manage its relations with the French crown. During his rule, John III faced challenges, including conflicts with the French monarchy. He was involved in the Hundred Years' War and sought alliances to protect Brittany's interests. John III died in 1341, leaving a legacy of striving for autonomy in a politically complex landscape.