From Wikipedia

Monarchy

Season Two
Episode One

The Crown Imperial

The Crown Imperial: 1450s and The Wars of the Roses, the birth of the Tudors.

The Wars of the Roses were a series of dynastic civil wars between supporters of the rival houses of Lancaster and York, for the throne of England. They are generally accepted to have been fought in several spasmodic episodes between 1455 and 1487 (although there was related fighting both before and after this period). The war ended with the victory of the Lancastrian Henry Tudor, who founded the House of Tudor, which subsequently ruled England and Wales for 116 years.