The name 'Kat Ashley', Queen Elizabeth's 'Governess', is well-known to fans of Tudor history. Katherine Champernowne, later John Astley's wife, joined Elizabeth's household before the future queen turned three. Later she became Elizabeth's 'governess', trusted with the upbringing of the King's younger daughter. Formidably well-educated for a woman of her time, reports suggest Katherine did an excellent job. When Elizabeth came to the throne, one of her first actions was to name Katherine as Chief Gentlewoman of the Bedchamber, a highly influential position within the court of a female monarch. Over nearly three decades, the two women developed an unshakeable bond. Katherine Astley served loyally during dangerous and uncertain times, enduring several spells of imprisonment. Her death, after a brief illness in July 1565, left the Queen devastated. Despite this, Katherine's true character remains largely unknown. There has even been widespread confusion about her identity and parentage. Yet the clues are there. Katherine was not from an obscure background in rural Devon, as is sometimes claimed. Her family ties placed her amongst influential figures close to the royal court and amongst scholars, humanist thinkers, and advocates of religious reform. Focussing on Thomas Seymour's inappropriate behaviour towards Elizabeth while she was in the household of his wife, Catherine Parr, has led historians to conclude that Katherine Astley showed poor judgement. Fictional portrayals and on-screen depictions often show Elizabeth's governess as a gossipy, middle-aged nanny. This biography offers a fresh perspective on Katherine's significance in Elizabeth's youth, and challenges traditional interpretations to produce a believable picture of the woman Queen Elizabeth I valued so highly.