The Family Tree: Roots of the Wars of the Roses: In the middle of the fifteenth century Henry VI, son of the great king Henry V, suffered a mental collapse and the governance of England was turned over to his cousin Richard, duke of York.
Henry's grandfather, Henry IV, had usurped the throne from Richard II and based his claim on being descended from the third surviving son of Edward III through direct male descent. Richard, duke of York, on the other hand, claimed descent from Edward III's second surviving son -- but through the female line. Claims and counterclaims turned to the clashes of arms we now call the Wars of the Roses, and Richard, duke of York was killed in battle on December 30, 1460. His son, the eighteen-year-old Edward, Earl of March (tall, blond, handsome, and eligibly single), took up the cause.
Edward defeated the forces of Henry VI in two brilliantly-fought battles and assumed the throne on June 28, 1461. Unfortunately for Edward, Henry VI was still very much alive, and so were many nobles still loyal to Henry.
So, who was the rightful king of England? This gripping question depended on the legitimacy of descent through the female line -- a claim that Henry V had advanced to justify his invasion of France, but which would paradoxically have barred him from claiming the very throne he occupied.
Additional web links:
Visit Britannia.com's Monarchs of Britain or Britannia page for brief biographies of medieval English kings
Use the University of Hull's Royal Genealogy Database to explore the overlapping family relationships of medieval English kings and nobility (like most genealogy databases, this is a work in progress and is regularly expanded or corrected)