This is the first biography of the fateful relationship between Elizabeth I and Mary Queen of Scots. It was the defining relationship of their lives, and marked the intersection of the great Tudor and Stuart dynasties, a landmark event in British history. Distinguished biographer Jane Dunn reveals an extraordinary story of two queens ruling in one isle, both embodying opposing qualities of character, ideals of womanliness and of divinely ordained kingship. Theirs is a drama of sex and power, recklessness, ambition and political intrigue, with a rivalry that could only be resolved by death. As regent queens in an overwhelmingly masculine world, they were deplored for their femininity, compared unfavourably with each other, and courted by the same men. By placing this dynamic and ever-changing relationship at the centre of the book, Dunn throws new light and meaning on the complexity of their natures. She reveals an Elizabeth revolutionary in her insistence on ruling alone, while Mary is not the romantic victim of history, but a courageous adventurer with a reckless heart. Vengeful against her enemies and the more ruthless of the two, she was untroubled by plotting Elizabeth's murder. Elizabeth, however, was in anguish at having to sanction Mary's death warrant for treason. Working almost exclusively from contemporary letters and writings, she lets them speak to us across more than four hundred years, their voices and responses surprisingly familiar to our own, their characters vivid, by turns touching and terrible.