Katherine Synford was first the mistress, and later the wife, of John of Gaunt, the Duke of Lancaster. Her charismatic lover was one of the most powerful princes of the fourteenth century and Katherine was renowned for her beauty and regarded as enigmatic, intriguing and even dangerous by some of her contemporaries. In her impressive new book, Alison Weir has triumphantly rescued Katherine from the footnotes of history, highlighting her key dynastic position within the English monarchy. She was the mother of the Beaufort, then the ancestress of the Yorkist kings, the Tudors, the Stuarts and every other sovereign since - a prodigious legacy that has shaped the history of Britain.