Kate Williams is a historian, author, professor of history and broadcaster. Her latest book, Rival Queens: The Betrayal of Mary Queen of Scots explores Mary’s queenship, the successes, mistakes and the doubts – and her great rivalry with Elizabeth I. Her other books are on Victoria, Elizabeth II, Emma Hamilton and Josephine Bonaparte and four novels, Pleasures of Men, Storms of War, Edge of the Fall and House of Shadows. She regularly discusses history and monarchy on TV and her most recent series is The Stuarts on Yesterday. She is the royal historian for CNN and has talked on monarchy on every programme from BBC Breakfast and Today to the British Bake Off and Countryfile.