James VI and I
His reign was important because it was the first time England and Scotland had the same monarch. He was the first monarch of England from the House of Stuart. The previous English monarch had been Elizabeth I. She had died without any children, so the English agreed to have a Scottish monarch because James was the son of Mary, Queen of Scots, thus the closest relative Elizabeth had. By being king of both, he created a personal union, the Union of the Crowns.