Edward IV of England Richard, Duke of Gloucester (later King Richard III of England), were married to Isabel Neville and Anne Neville. Both were daughters of Warwick by Anne Beauchamp and rival heirs to the considerable inheritance of their still-living mother, leading to a dispute between the brothers. In 1478 George was eventually found guilty of plotting against Edward, imprisoned in the Tower of London, and privately executed on 18 February 1478. According to a long-standing tradition, he was "drowned in a butt of Malmsey wine". Edward did not face any further rebellions after his restoration, as the Lancastrian line had virtually been extinguished.
The True Tragedy of Richard III a source for his play, though the majority tend to favour this judgement. Geoffrey Bullough treats "The True Tragedy" as a "probable source" for "Richard III", citing several commonalities (as when, in both plays, Richard calls for a horse on Bosworth Field, yet refuses to flee the battle) — though Bullough admits that the nature of the plays' relationship is "not clear." The uncertainty in dating has allowed a few commentators to propose a reversed priority, and to argue that the author (or reviser) of "The True Tragedy" may have borrowed from Shakespeare's play. Shakespeare appears to have known of