Elizabeth was the wife of King Henry VII and the mother to the future King Henry VIII. Their union began the “Tudor” period as we know it. She married Henry in 1486 after his victory at the Battle of Bosworth Field against the other claimant to the throne, Richard III, which marked the end of the Wars of the Roses. The War of the Roses was one of the most tumultuous periods of English history, involving two main warring factions, the Yorkists and the Lancastrians. Both sides were vying for the throne and both sides had legitimate claims. The marriage of Elizabeth of York and Henry VII (of Lancaster), marked a political union that worked as intended - to show that the war was over, and that the two sides had joined. Obviously there is much more nuance to the events, but that is the cliff-notes version.