The Avignon papacy (1309–1377) represented the zenith of papal power in Europe. The Roman curia’s move to southern France enlarged its bureaucracy, centralized its authority, and initiated closer contact with secular institutions. The pope’s presence also attracted leading minds to Avignon, transforming a modest city into a cosmopolitan center of learning. But a crisis of legitimacy was brewing among leading thinkers of the day. The Avignon Papacy Contested considers the work of six fourteenth-century writers who waged literary war against the Catholic Church’s increasing claims of supremacy over secular rulers—a conflict that engaged contemporary critics from every corner of Europe.

Unn Falkeid uncovers the dispute’s origins in Dante’s Paradiso and Monarchia, where she identifies a sophisticated argument for the separation of church and state. In Petrarch’s writings she traces growing concern about papal authority, precipitated by the curia’s exile from Rome. Marsilius of Padua’s theory of citizen agency indicates a resistance to the pope’s encroaching power, which finds richer expression in William of Ockham’s philosophy of individual liberty. Both men were branded as heretics. The mystical writings of Birgitta of Sweden and Catherine of Siena, in Falkeid’s reading, contain cloaked confrontations over papal ethics and church governance even though these women were later canonized.

While each of the six writers responded creatively to the implications of the Avignon papacy, they shared a concern for the breakdown of secular order implied by the expansion of papal power and a willingness to speak their minds.

A dual biography crafted around the famous encounter between the French philosopher who wrote about power and the Russian empress who wielded it with great aplomb.

In October 1773, after a grueling trek from Paris, the aged and ailing Denis Diderot stumbled from a carriage in wintery St. Petersburg. The century’s most subversive thinker, Diderot arrived as the guest of its most ambitious and admired ruler, Empress Catherine of Russia. What followed was unprecedented: more than forty private meetings, stretching over nearly four months, between these two extraordinary figures. Diderot had come from Paris in order to guide—or so he thought—the woman who had become the continent’s last great hope for an enlightened ruler. But as it soon became clear, Catherine had a very different understanding not just of her role but of his as well. Philosophers, she claimed, had the luxury of writing on unfeeling paper. Rulers had the task of writing on human skin, sensitive to the slightest touch.

Diderot and Catherine’s series of meetings, held in her private chambers at the Hermitage, captured the imagination of their contemporaries. While heads of state like Frederick of Prussia feared the consequences of these conversations, intellectuals like Voltaire hoped they would further the goals of the Enlightenment.

In Catherine & Diderot, Robert Zaretsky traces the lives of these two remarkable figures, inviting us to reflect on the fraught relationship between politics and philosophy, and between a man of thought and a woman of action.