The Battle of Bosworth or Bosworth Field was the last significant battle of the Wars of the Roses, the civil war between the houses of Lancaster and York that extended across England and Wales in the latter half of the 15th century. Fought on 22 August 1485, the battle was won by an alliance of Lancastrians and disaffected Yorkists. Their leader Henry Tudor, Earl of Richmond, became the first Welsh monarch of England from the House of Tudor by his victory and subsequent marriage to the de facto Yorkist heiress, Elizabeth of York. His opponent Richard III, the last king of the House of York, was killed during the battle, the last English monarch to fall in battle. Historians consider Bosworth Field to mark the end of the Plantagenet dynasty, making it one of the defining moments of English history.