The Borgias dominate the Renaissance, fascinating across time with their power, their charm, and their unsavory reputations. They have inspired countless books, movies, scholarly works, and rumors, and the one thing everyone can agree on is just how difficult they are to pin down: corrupt churchman and his incestuous brood, or loving paterfamilias and his misunderstood offspring? The truth is probably somewhere in the middle—and pure gold to a historical novelist.

It’s fashionable to blame the Borgias for corrupting the Church, but the institution was already corrupted long before Rodrigo Borgia took the throne of St. Peter as Alexander VI. Benefices, pardons, and indulgences were openly bought and sold; vows of chastity and poverty among the clergy were blatantly ignored, and the Pope was politician and king over his unruly papal states just as much as he was Father of Christendom. Priests like Savonarola preached of the dangers of sin and hellfire, but it was understood by even the lowest on the social scale that there was no sin that could not be pardoned with the appropriate penance or payoff. The Borgias have become the poster children for this cynical system, but their real sin appears to be their lack of hypocrisy: Rodrigo Borgia was hardly the first Pope to aggrandize his family, keep a mistress, or sire illegitimate children; he simply refused to hide any of it under the usual cloak of lies. Such honesty about his various sins might be rather refreshing to a modern perspective—not so to his contemporaries.

Giulia Farnese was one of the great beauties of the Renaissance, already famous for her vivacity and her floor-length hair by the time she married wealthy young Orsino Orsini. It isn’t known precisely when Giulia caught the eye of the womanizing Rodrigo Borgia, or if her marriage to Orsino was arranged from the beginning as a cover for an illicit affair—Rodrigo arranged several such compliant husbands for his previous mistress, Vannozza dei Cattanei. But by the time Cardinal Borgia was elected Pope, Giulia Farnese was his official mistress, installed in a cheerful domestic arrangement with her apparently compliant mother-in-law, Adriana da Mila, and the young Lucrezia Borgia. The deftness with which Giulia handled her volatile Pope throughout their long and evidently passion-filled affair indicates that the woman nicknamed the Bride of Christ had some brains under all that hair.