Simplify the following text for a Grade 9 native English-speaking person.
Original: 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 .
Simplified: 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 .