 Elisabeth, Princess Palatine of Bohemia (1618–1680) is most well-known for her extended correspondence with René Descartes, and indeed these letters constitute what we currently know of her extant philosophical writings. In that correspondence, Elisabeth presses Descartes on the relation between the two really distinct substances of mind and body, and in particular the possibility of their causal interaction and the nature of their union. They also correspond on Descartes’s physics, on the passions and their regulation, on the nature of virtue and the greatest good, on the nature of human freedom of the will and its compatibility with divine causal determination, and on political philosophy. Descartes dedicated his Principles of Philosophy to Elisabeth, and wrote his Passions of the Soul at her request. While there is much to be learned about Descartes’s philosophical views by reading this exchange, this entry is not focused on its relevance for understanding Descartes, but rather to summarize Elisabeth’s own philosophical views. We are now also aware of additional correspondence with scientists of the period, as well as extensive family correspondence. Elisabeth seems to have been involved in negotiations around the Treaty of Westphalia and in efforts to restore the English monarchy after the English civil war. As Abbess of Herford (Germany) convent, she managed the rebuilding of that war-impacted community and also provided refuge to marginalized Protestant religious sects, including Labadists and Quakers.