Charles Hector de St. Georges, Marquis de Marsay (1688–1753), lived for the greater part of his life in the small and obscure principality of Wittgenstein in the upper Eder valley between the Rhineland and Hesse-Kassel. In his earlier years he was a disciple of the Flemish mystic, Antoinette Bourignon, and later came under the influence of the works of Madame Guyon. In Wittgenstein he attempted to put their teachings into practice by following an ascetic pattern of life. He attracted a number of followers, not only from the sectarian groups which had taken refuge in Wittgenstein, but also farther afield, notably in Switzerland, which he visited on a number of occasions. The fact that he was known in Britain to John Wesley and William Law, as well as by the group of mystically inclined gentry in north-east Scotland, is an indication of the contacts that existed between pietistic groups in different parts of Europe. The details of Marsay's life are not without interest is a considered attempt to practice the quietist spirituality of Madame Guyon in a Protestant context.