Richard of York, 3rd Duke of York KG (21 September 1411 – 30 December 1460), was a leading English magnate, a great-grandson of King Edward III through his father, and a great-great-great-grandson of the same king through his mother. He inherited vast estates and served in various offices of state in Ireland, France, and England, a country he ultimately governed as Lord Protector during the madness of King Henry VI. His conflicts with Henry's wife, Margaret of Anjou, and other members of Henry's court, as well as his competing claim on the throne, were a leading factor in the political upheaval of mid-fifteenth-century England, and a major cause of the Wars of the Roses. Richard eventually attempted to take the throne, but was dissuaded, although it was agreed that he would become king on Henry's death. But within a few weeks of securing this agreement, he died in battle.