Book excerpt: In this sweeping history, Trevor Royle details one of the bloodiest episodes in British history. The prize was the crown of England, and the players were the rival houses of Lancaster and York. The dynastic quarrel threatened the collapse of the monarchy as a succession of weak rulers failed to deal with an overzealous aristocracy, plunging England into a series of violent encounters. The bloody battles and political intrigue between the rival heirs of King Edward III brought forth one of the most dynamic ruling families of England--the Tudors.