Thomas Day was wealthy and educated and ran in influential circles. But there was one problem. The 18th-century British philosopher’s lack of interest in polite manners and fashion—and, more important, personal hygiene—made it difficult for him to attract a suitable mate.

Day liked to quote a line from a poem titled “Advice to the Ladies”: “Wit like wine intoxicates the brain/Too strong for feeble women to sustain.” A great benefactor to the poor and a vocal champion of the American Revolution, Day wrote passionate diatribes about the need to free African slaves and lobbied to expand voting rights to include men of all classes. But where women were concerned, Day’s views were far less progressive. It seems only fitting that after his death, Day’s eccentric life story has been most vividly recounted by a series of women: first, by Anna Seward, a friend and contemporary; then by Maria Edgeworth, a celebrated novelist (and the daughter of Day’s best friend, Richard Edgeworth); and, most recently, biographer Wendy Moore. In How to Create the Perfect Wife, Moore retells the story of Day’s attempt to fashion the ideal bride out one of two 12-year-old orphans he took in as “maid apprentices” from London’s Foundling Hospital.

The notion of handcrafting a flawless spouse was nothing new—the Pygmalion myth dates back to ancient Greece. Still, Day’s scheme was shocking in its perverse simplicity. By the time he was a university student, Day had refined a strict set of ideas on what qualities defined the ideal woman. He wanted purity, docility, absolute devotion to her husband—and plump white arms. He had an idea about what the perfect marriage would look like, too: upon matrimony, his wife would, as Moore recounts, “renounce all her comforts and company to live with him in isolated penury devoting her life to doing good works.”

So, inspired by Jean-Jacques Rousseau’s writings on education, Day hatched a scheme to mold an untrained, unattached young girl into a creature of the right temperament, disposition, and devotion to become his bride—or two of them. Unbeknownst to his apprentice maids, Day intended to test out the teaching methods laid out in Rousseau’s Émile—not an education manual, but a novel. Using a rigorous course of philosophy texts, chores, and exposure to the elements, he hoped to transform at least one of his unsuspecting young adoptees into a physically hardy, industrious, and chaste companion.

When Lucretia, the younger blonde, displayed a stubborn dislike for her studies, Day sent her away to be apprenticed to a milliner and doubled down on Sabrina, the brunette. Sabrina was studious and eager to please. And why wouldn’t she be? Day completely controlled her fate—he was employer, protector, and tutor all rolled into one. But her master’s demands were confusing. Moore finds no indication that Day took sexual advantage of his ward, but he commanded her body in other ways. He bizarrely poured hot wax on her skin and fired a pistol at her skirts to test her fearlessness. When Sabrina flinched, Day’s confidence in her faltered. Pausing the experiment, Day enrolled Sabrina in boarding school and turned his attention to other marital prospects.

Lo and behold, Sabrina returned a refined, charming lady, and Day promptly revealed his grand plan to wed her. Sabrina was initially horrified. But with no trade, no income, and no family, her options were limited.

Then, at the last minute, Day called off the wedding, accusing Sabrina of violating “particular injunctions.” It was his fourth broken engagement. Day’s search for the perfect woman—rather, his manipulation of a human being—wasn’t a means but an end in itself. After still one more failed engagement, Day married Esther Milnes, a brainy heiress who was utterly enchanted with his ideas. Day “tried endlessly to correct Esther to meet his strictures,” Moore writes. “He was forever disappointed.”

What’s surprising is how things end for Sabrina. Despite the havoc Day’s unconventional education wreaked on her reputation, his rejection finally gave her a chance to shape her own fate. After her “apprenticeship” ended, she married a friend of Day’s, raised two children, and worked as a housekeeper, saving up £2,000 (an amount worth more than half a million dollars today) to pass on to her children and seven grandchildren after her death. In light of the circumstances, her resilience seems nothing short of defiant. Nonetheless, Sabrina remains something of a cipher in Moore’s account. Day enjoyed the friendship of many prominent intellectuals (the grandfather of Charles Darwin, among others), and their gossipy letters provided Moore with much of the source material. But while Sabrina occasionally exchanged polite letters with members of Day’s circle, they reveal little about her own interpretation of the experiment apart from deep mortification at having her story told and retold.

How could Day himself remain blind to his hypocrisy? And why did none of his friends stop him? That’s a difficult question, and in the places where historical documentation falls short, Moore turns the gaps into opportunities to revel in the lurid injustice of Sabrina’s fate. Here, she follows a long tradition of writers. Henry James reshaped Day’s story for his first novel, Watch and Ward; Maria Edgeworth featured characters based on Day and Sabrina in her famous novel Belinda; Fanny Burney and Anthony Trollope riffed on the story too. These fictional renditions are largely love stories. Moore’s research suggests the real-life Sabrina got by not on love but on reserves of inner strength and dignity. If Day’s experiments shaped her, it was certainly not in the way he intended.