With Liz I’s death in 1603, the Tudor line ended and the Stuart line began with James I. Well, he was James VI of Scotland, but became James I of England and Ireland.
Follow me, here: Scotland had had a separate monarchy since the 9th century, when it became its own country. There were five King Jameses there before Liz’s future heir became Scotland’s king. He was only 13 months old when his mother, Mary Queen of Scots, was whisked away and imprisoned. She later fled to England where she spent 19 years and then became about a foot shorter.
Little James VI had adults to rule for him, of course, until he reached the age of majority, but he was technically the king of Scotland for 36 years before swinging on down to London as the new top dog. And since England had never had a King James previously, he became James I there.
Why do we sometimes see Life After Tudors spelled “Stewart” rather than “Stuart”? It was “Stewart” originally, from way back in the 9th century, but James’ mom, Mary Q of S, actually grew up in France. There was no “w” in the French alphabet at the time, and she would have spelled it “Stuart.”
Scotland and France were BFFs during the Tudor period, and occasionally beyond that, so “Stewart” and “Stuart” were used interchangeably to describe that post-Tudor dynasty, depending on whether the Scots and the French were playing nicely. Now it is usually spelled “Stuart.” Either way, it spelled d-r-a-m-a f-r-e-e for the most part, until the Gunpowder Plot a few years later.