Original: 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.
Simplified: It was fought on 22 August, 1485 between the Yorkist King Richard III, the last of the Plantagenet dynasty, and the Lancastrian Henry Tudor, 2nd Earl of Richmond, who wanted to become king.