Marquis de, a French mystic, was born in 1688 at Paris, whither his parents, pious members of the Reformed Church, had fled to avoid the persecution raging against the Protestants in the provinces. While yet a youth the whole family removed to Germany- and there Charles I took part in the Spanish War of Succession in the Netherlands. He now became a convert to the views of Bourignon (q.v.), and with his friend Cordier retired, in 1711, to Schwarzenau, in the province of Wittgenstein. Cordier, however, leaving him, he married, in 1712, Clara Elizabeth of Callerberg, whose views were similar to his own. During the years 1713-16 he made several journeys to Switzerland, where he became acquainted with the works of Madame Guyon (q.v.). He then returned to Schwarzenau, learned the watch-making trade, became president of the Philadelphian Society, and resided there until 1724. In 1746 he became a Pietist, and died in the neighborhood of Ambleben in 1753, a truly evangelical Christian, a disciple of Christ, clinging faithfully to the truth as it is in Jesus. Marsay had great influence in propagating throughout Germany the mystic views of Bourignon and Guyon. He wrote Freimüthige u. christliche Discurse (1734): — Zeugniss eines Kindes v. d. Richtigkeit d. Wege d. Geistes (1735, 2 parts): —Selbstbiographie, in the 2d vol. of Valenti, System d. hoheren Heilkunde (Elberf. 1826). — Gobel, Gesch. der wahren Inspirations-gemeinden (in Niedner's Zeitschr. f. hist. Theol. 1855, 3, § 21, 4); the same, Gesch. d. christl. Lebens, etc. (Cobl. 1852), 2, bk. 9; also the excellent article in Herzog, Real-Encyklop. 9:116 sq.