CALIXTUS, GEORG (1586-1656), Lutheran divine, was born at Medelbye, Schleswig, on Dec. 14, 1586. After studying philology, philosophy and theology at Helmstedt, Jena, Giessen, Tubingen and Heidelberg, he travelled through Holland, France and England, where he became acquainted with the leading re. formers. On his return in 1614 he was appointed professor of theology at Helmstedt by the duke of Brunswick, who had ad mired the ability he displayed when a young man in a dispute with the Jesuit Augustine Turrianus. Calixtus held this post for 40 years, and made Helmstedt a centre of reasonableness in an age of bitter theological controversy. He constantly pressed for a milder treatment of confessional differences, and thought that a basis for the reunion of all the churches could be found in the study of the Christian fathers. His ideas were those later advo cated (also fruitlessly) by Leibnitz. In 1613 he published a book, Disputationes de praecipuis religionis christianae capitibus, which provoked the hostile criticism of orthodox scholars; in 1619 he published his Epitome theologise, and some years later his Theo logic Months (1634) and De Arte Nova Nihusii. Statius Buscher charged the author with a secret leaning to Romanism. Calixtus refuted the accusation of Buscher, but after the conference of Thorn (1645), a new charge was preferred against him, prin cipally at the instance of Abraham Calovius (1612-1686), of a secret attachment to Calvinism. The disputes on the possibilities of the reconciliation desired by Calixtus known in the Church as the Syncretistic controversy, lasted during the whole lifetime of Calixtus, and distracted the Lutheran Church, till a new contro versy arose with P. J. Spener and the Pietists of Halle. Calixtus died on March 16, 1656.
See E. L. T. Henke, Georg Calixtus and seine Zeit (1853-6o) ; also Isaak Dorner, Gesch. d. protest. Theol. pp. 606-624 ; and especially Herzog-Hauck, Realencyklopddie.