Early modern rulers believed that the more subjects over whom they ruled, the more powerful they would be. In 1666, France's Louis XIV and his minister Jean-Baptiste Colbert put this axiom into effect, instituting policies designed to encourage marriage and very large families. Their Edict on Marriage promised lucrative rewards to French men of all social statuses who married before age twenty-one or fathered ten or more living, legitimate children. So began a 150-year experiment in governing the reproductive process, the largest populationist initiative since the Roman Empire. Conceiving the Old Regime traces the consequences of premodern pronatalism for the women, men, and government officials tasked with procreating the abundant supply of soldiers, workers, and taxpayers deemed essential for France's glory. While everyone knew-in a practical rather than a scientific sense-how babies were made, the notion that humans should exercise control over reproduction remained deeply controversial in a Catholic nation. Drawing on a wealth of archival sources, Leslie Tuttle shows how royal bureaucrats mobilized the limited power of the premodern state in an attempt to shape procreation in the king's interest. By the late eighteenth century, marriage, reproduction, and family size came to be hot-button political issues, inspiring debates that contributed to the character of the modern French nation. Conceiving the Old Regime reveals the deep historical roots of France's perennial concern with population, and connects the intimate lives of men and women to the public world of power and the state.