1403-1444 - John Beaufort, Duke of Somerset - Wimborne Minster, Dorset eldest son of John of Gaunt. Margaret Beaufort's father. Henry VII's grandfather. Believed to have commited suicide after a quarrel with the government led him to the disgrace of banishment from court. Henry VII' s best blood claim to the throne actually came through this Beaufort line, which was descended from a mistress (and later wife) of John of Gaunt named Katherine Swynford.