In the history of European ideas, Princess Elisabeth is conventionally viewed as little more than a curiosity, a clever but ultimately unimportant exiled princess who became the confidant, critic, and muse of a far more famous man, René Descartes. Contrary to this view, however, this article argues that Elisabeth made a significant contribution to the development of western philosophy in her own right. Drawing on her letters to Descartes, as well the diaries and correspondence of her associates and a range of secondary sources, it demonstrates that an early understanding of the modern emotions akin to that which later found form in the work of the moral sentiment theorists can be found in Elisabeth’s thought. In particular, drawing on her understanding of the embodied mind, Elisabeth of Bohemia began to develop a hybrid understanding of the passions, identified a role for the emotions in the pursuit of virtue, and began to reconceive the relationship between reason and the emotions that had until then dominated seventeenth-century thought.