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 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 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 during the battle, the last English monarch to die in combat. Historians consider Bosworth Field to mark the end of the Plantagenet dynasty, making it one of the defining moments of English history.

The Wars of the Roses, known at the time and in following centuries as the Civil Wars, were a series of civil wars fought over control of the English throne from 1455 to 1487. The wars were fought between supporters of the House of Lancaster and House of York, two rival cadet branches of the royal House of Plantagenet. The conflict resulted in the end of Lancaster's male line in 1471, enabling the Tudor family to inherit their claim to the throne through the female line. Conflict was largely brought to an end upon the union of the two houses through marriage, creating the Tudor dynasty that would subsequently rule England.