A stunning portrait of Katherine Swynford, a royal mistress who became one of the most crucial figures in the history of Great Britain, from the New York Times bestselling author hailed as “the finest historian of English monarchical succession writing” ( The Boston Globe ) “Weir brings alive the brilliant beauty whose descendants would sit on the British throne.”— USA Today Born in the mid-fourteenth century, Katherine de Roët was only twelve when she married Hugh Swynford, an impoverished knight. But her story had truly begun two years earlier, when she was appointed governess to the household of John of Gaunt, Duke of Lancaster and fourth son of King Edward III. Widowed at twenty-one, Katherine became John’s mistress and then, after many twists of fortune, his bride in a scandalous marriage. Drawing on rare documentation, Mistress of the Monarchy reveals a woman ahead of her time—making her own choices, flouting convention, and taking control of her own destiny. Indeed, without Katherine Swynford, the course of English history, perhaps even the world, would have been very different. “For those interested in the rarified realms of medieval British royalty, its trappings, intrigues, excesses, cruelties, and sex scandals, [ Mistress of the Monarchy ] will be gratifying.” — The Star-Ledger “One of history’s greatest love stories . . . Swynford’s colorful life played out against a backdrop of court life at the height of the age of chivalry.” — Wisconsin State Journal “Weir has accomplished a seemingly impossible task [in writing a] biography about a woman who left behind not a single image and not a single written word. . . . Weir’s meticulous and scholarly research has unearthed details that help bring Katherine to life.” — Fredericksburg Free Lance-Star “Quite beguiling. Bowled over by this tale of true love, Weir recaptures its glow in a fluid, artfully assembled narrative.” — Kirkus Reviews “The historical research is meticulous and seamlessly integrated into the narrative. The result is a story of a real woman with virtues, flaws, and an altogether fascinating life.” — Historical Novels Review Alison Weir is the New York Times bestselling author of the novels Innocent Traitor and The Lady Elizabeth and several historical biographies, including Mistress of the Monarchy, Queen Isabella, Henry VIII, Eleanor of Aquitaine, The Life of Elizabeth I , and The Six Wives of Henry VIII . She lives in Surrey, England with her husband and two children. Chapter One Panetto's Daughter Katherine Swynford, that famous adulteress,1 was set on the path to notoriety, fame, and a great love at the tender age of two or thereabouts, when she was placed in the household of Philippa of Hainault, wife to Edward III of England. This would have been around 1352, and Katherine's disposition with the popular and maternal Philippa was almost certainly due to her father, Sir Paon de Roët, having rendered years of faithful service to the Queen and the royal family of Hainault. Like her benefactress, Katherine was a Hainaulter. She was born Katherine de Roët, her surname variously given as Rouet, Roëlt, or Ruet, and pronounced Roay. The Roëts were a prominent family in Hainault, then an independent principality located in the western reaches of the Holy Roman Empire, bordering on the kingdom of France and occupying much of what is now Belgium. This fertile and prosperous county stretched from Liège and Brussels in the north to Lille and Valenciennes in the south, and contained other thriving cloth cities: Mons, Charleroi, and Tournai; all of which provided a market for England's raw wool, her chief export. Formed at the time of the division of Charlemagne's empire in the ninth century, Hainault had been an imperial fief since 1071, and in the early fourteenth century it was ruled by the House of Avesnes, which had come to power in 1244. Katherine possibly had noble or even royal connections through her mother, but claims that she was closely related through her father to the aristocratic lords of Roeulx cannot be substantiated. The Roeulx were a great and powerful Hainaulter family that could trace its descent from the ancient counts of Flanders and Hainault, who were themselves descended from the Emperor Charlemagne, and from England's famous King Alfred. William the Conqueror had married a princess of that house, Matilda of Flanders, and by her was the founder of the ruling dynasties of England, the Norman and Plantagenet kings. Since the twelfth century the lords of Roeulx had prospered mightily.2 Their landholdings centered mainly on the town of Le Roeulx, which lies eight miles northeast of Mons, but their name is also associated with Roux, forty miles east of Mons, and Fauroeulx, twenty miles to the south. That Katherine shared a close kinship with the lords of Roeulx is doubtful on heraldic evidence alone—or the lack of it.3 Her family was relatively humble. The chronicler Jean Froissart, a n