John II of Brittany was a notable duke who ruled from 1341 to 1372. He was born in 1330 and became the Duke of Brittany after a period of conflict over succession. His reign was marked by struggles against both internal factions and external threats, particularly from the Kingdom of France. During his rule, John II sought to strengthen the duchy's independence and maintain its unique identity. He was involved in the Hundred Years' War, aligning with the English at times, which complicated his relationships with neighboring powers. His efforts laid the groundwork for future stability in Brittany.