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. At its core were their rival claims to the throne of England.

Distinguished biographer Jane Dunn reveals an extraordinary story of two queens ruling in one isle, both embodying opposing qualities of character, ideals of womaliness and 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 regnant queens in an overwhelmingly masculine world they were deplored for their femaleness, 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 and inspired in her use of celibacy as a political tool, yet deeply feeling and more sympathetic than the usual picture of the virgin queen. Mary, too, is not the romantic victim of history but a courageous adventurer with a reckless heart, and a magnetic influence over men and women alike. 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.

Jane Dunn brings her skills as a biographer to bear on history's two most charismatic queens. Working almost exclusively from contemporary letters and writings, she lets them speak to us across more than 400 years, their voices and responses surprisingly familiar to our own, their characters vivid, by turns touching and terrible. The death in 1603 of Elizabeth, our greatest English queen, was to mark the end of the Tudors and the posthumous triumph of Mary, whose son, James I united the English and Scottish thrones under a Stuart king.