John, Lord of Beaufort was descended from one branch of the English royal dynasty of the Plantagenets. Born before May 1286, he was the third and youngest son of Edmund Crouchback, 1st Earl of Lancaster and Leicester, and Blanche of Artois. His father was the second son of King Henry III of England, making John the nephew of King Edward I of England and the cousin of King Edward II of England. His mother Blanche was the daughter of Count Robert I of Artois, son of King Louis VIII of France and brother of King Louis IX. Due to his mother's first marriage to King Henry I of Navarre, John was thus the half-brother of Queen Joan I of Navarre and the uncle of King Louis X of France, King Philip V of France, and King Charles IV of France and Navarre.