CALIXTUS, GEORG (1586-1656), Lutheran divine, was born at Medelby, a village of Schleswig, in 1586. After studying philology, philosophy and theology at Helmstädt, Jena, Giessen, Tübingen and Heidelberg, he travelled through Holland, France and England, where he became acquainted with the leading Reformers. On his return in 1614 he was appointed professor of theology at Helmstädt by the duke of Brunswick, who had admired the ability he displayed when a young man in a dispute with the Jesuit Augustine Turrianus. 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 theologiae, and some years later his Theologia Moralis (1634) and De Arte Nova Nihusii. Roman Catholics felt them to be aimed at their own system, but they gave so great offence to Lutherans as to induce Statius Buscher to charge the author with a secret leaning to Romanism. Scarcely had he refuted the accusation of Buscher, when, on account of his intimacy with the Reformed divines at the conference of Thorn (1645), and his desire to effect a reconciliation between them and the Lutherans, a new charge was preferred against him, principally at the instance of Abraham Calovius (1612-1686), of a secret attachment to Calvinism. In fact, the great aim of his life was to reconcile Christendom by removing all unimportant differences. The disputes to which this attitude gave rise, known in the Church as the Syncretistic controversy, lasted during the whole lifetime of Calixtus, and distracted the Lutheran church, till a new controversy arose with P.J. Spener and the Pietists of Halle. Calixtus died in 1656.
There is a monograph on Calixtus by E.L.T. Henke (2 vols., 1853-1856); see also Isaak Dorner, Gesch. d. protest. Theol. pp. 606-624; and especially Herzog-Hauck, Realencyklopädie.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)