Of Henry VIII’s six wives, Katherine of Aragon enjoyed the longest and most complicated relationship with the King. First, she was his sister-in-law, escorted at sixteen by the ten year old Henry to marry his elder brother, Arthur. Next, she was a widowed princess in financial and diplomatic limbo, rescued from this uncertainty by Henry’s ascension to the throne and proposal of marriage. As Henry VIII’s first wife, she was his friend, lover and advisor. She served as regent of England while her husband fought the French, organizing the defense of England against the Scots. She was the mother of the future Queen Mary I, and numerous other children who died in infancy. In the end, Katherine was Henry’s victim and adversary in “The King’s Great Matter,” asserting the validity of her marriage and her status as Queen until her dying breath.

Despite this variety of experience, Katherine’s biographers traditionally assumed her to be a saintly woman whose relationship with Henry superseded all other concerns. Garrett Mattingly’s beautifully written biography, Catherine of Aragon, is the story of a woman wronged by her husband’s infatuation with Anne Boleyn. In collective biographies of Henry VIII’s wives by Agnes Strickland, Alison Weir and Antonia Fraser, Katherine’s twenty year marriage receives the same amount of space as the much shorter marriages of the subsequent five queens, simplifying the ever changing relationship between Henry and Katherine.

Only recently has David Starkey questioned Katherine’s supposed uncomplicated, saintly character in Six Wives: The Queens of Henry VIII and Giles Tremlett analyzed her enduring connections to her Spanish family in Catherine of Aragon: The Spanish Queen of Henry VIII.Julia Fox, the author of Jane Boleyn: The True Story of the Infamous Lady Rochford combines Starkey’s admiration for Katherine’s skills as a diplomat and public figure with Tremlett’s close analysis of Spanish documents in a well written and innovative joint biography of Queen Katherine and her sister Juana. Sister Queens: The Noble, Tragic Lives of Katherine of Aragon and Juana, Queen of Castile reveals that the daughters of King Ferdinand of Aragon and Queen Isabella of Castile were astute, educated, resourceful women who attempted to preserve the interests of their children through periods of political upheaval.

One of the great strengths of Sister Queens is Fox’s attention to the settings were these two princesses spent their lives. She has clearly traveled extensively in England, Wales and Spain and describes the Alhambra Palace in Grenada where Katherine and Juana spent part of their childhood, Ludlow Castle where Katherine lived during her brief time with Arthur and the numerous estates that comprised Katherine’s dower lands during her marriage to Henry VIII in exquisite detail. The households and responsibilities of both Katherine and Juana are also extensively discussed, revealing the precise responsibilities of a princess and queen in the sixteenth century.

Fox has a keen eye for the art and culture of sixteenth century European courts, describing the books owned by Catherine and Juana, the images woven into the tapestries in their chambers and the objects that decorated their palaces. This approach provides fresh insights into the worldview of two Spanish princesses who played such significant roles in the English and Flemish courts.

The sad life of Juana’s long life as the imprisoned Queen of Castile provides an effective counterpoint to Katherine’s experiences as Queen of England, revealing the challenges faced by royal women in a male dominated era of dynastic marriage. Juana has gone down in history as “Juana la Loca,” famously traveling around Spain with her husband’s coffin because she supposedly could not bear to be separated from his remains.

Fox makes a convincing case for Juana’s sanity, arguing that she was the victim of the political machinations of her father, Ferdinand of Aragon, her husband, Philip the Handsome of Flanders and her eldest son, Charles V of the Holy Roman Empire who all wanted direct control over her inheritance. The popular perception that Juana was insane and therefore unfit to rule provided a useful pretence for her enforced seclusion. Since Juana has been the subject of only one previous major English language work, Juana the Mad: Sovereignty and Dynasty in Renaissance Europe, I would have been interested to read more of Fox’s insights about this controversial Queen.

Sister Queens: The Noble, Tragic Lives of Katherine of Aragon and Juana, Queen of Castileis an engaging dual biography of two fascinating Queens that reveals the full complexity of their personalities and  goals. Fox also provides as fascinating portrait of the art and culture of the sixteenth century courts of Europe, demonstrating that Katherine and Juana were cultural patrons as well as political figures.