Bertrand du Guesclin was a prominent French military leader during the Hundred Years' War, which lasted from 1337 to 1453. Born around 1320 in Brittany, he became known for his strategic skills and leadership in battles against the English forces. Du Guesclin played a crucial role in several key victories, helping to reclaim French territories. He was appointed as the Constable of France in 1370, a position that made him the highest-ranking military officer in the country. His tactics often involved guerrilla warfare, which proved effective against the better-equipped English army. Du Guesclin's legacy is remembered as a symbol of French resistance and patriotism.