High Quality Content by WIKIPEDIA articles! The Battle of Bosworth Field (or the Battle of Bosworth) was the penultimate battle of the Wars of the Roses, the civil war between the House of Lancaster and the House of York that raged across England in the latter half of the 15th century. Fought on 22 August 1485, the battle was won by the Lancastrians. Their leader Henry Tudor, Earl of Richmond, became the first English monarch of the Tudor dynasty by his victory and subsequent marriage to a Yorkist princess. His opponent Richard III, the last king of the House of York, was killed in the battle. Historians consider Bosworth Field to mark the end of the Plantagenet dynasty, making it one of the defining moments of English history.