Margaret gained the support of the Scottish queen Mary of Guelders, and with a Scottish army she pillaged into southern England. The citizens of London feared the city being plundered and enthusiastically welcomed York's son Edward, Earl of March. Margaret's defeat at the Battle of Towton confirmed Edward's position and he was crowned. Disaffected with Edward's marriage to Elizabeth Woodville and preferment of her formerly Lancastrian-supporting family, Warwick and Clarence defected to the Lancastrians. The alliance was sealed with the marriage of Henry's son Edward to Anne, Warwick's daughter. Edward and Richard, Duke of Gloucester, fled England. When they returned, Clarence switched sides at the Battle of Barnet and Warwick and his brother were killed. Henry, Margaret and Edward of Lancaster were caught at the Battle of Tewkesbury before they could escape back to France. Edward of Westminster, Prince of Wales, was executed on the battlefield and John Beaufort, Marquess of Dorset, was killed in the fightingmeaning that when his brother Edmund Beaufort, 4th Duke of Somerset, was executed two days later, the Beaufort family became extinct in the legitimate male line. The captive Henry was murdered on 21 May 1471 in the Tower of London and buried in Chertsey Abbey, extinguishing the House of Lancaster.