Simler, Josias, a prominent Swiss theologian, was born Nov. 6, 1530, at Cappel, near Zurich, being the son of a prior who had quitted the convent there and married. Young Simler had applied himself with success to belles lettres, the sciences, and theology, devoting several years to visiting the principal schools of Germany; and on his return to Zurich in 1549, he first assisted Conrad Gessner in the chair of mathematics, and afterwards was appointed to the exposition of the New Test. (1552) in the capacity of deacon in the Church of St. Peter. In 1563 he succeeded Bibliander (q.v.) and Vermigli in the theological chair at Zurich, and distinguished himself by an immense literary activity, in addition to a faithful performance of the duties of his office. He was twice married, and left by his second wife four children. Though greatly afflicted with gout, he possessed an exceedingly amiable disposition, and was fond of society, given to hospitality and benevolent.
He died of gout, July 2, 1576. His life, was written by his colleague Stucki, of Zurich (1577), and his writings are catalogued in Gessner's Bibliotheca, amplified by Frisium (Zurich, 1583). Letters addressed to him from Hungary may be found in Miscell. Tiqur. 2, 213 sq., and in the Zurich Letters of the Parker Society. Comp. also Trechsel, Antitrinitarian, 2, 377 sq. Simler's works deal with astronomy, geography, history, biography, and statistics, no less than with theology. He republished Gessner's Bibliotheca Universalis in an abridged but much improved form (1555 and 1574). His Republ. Helvetiorum was translated into three languages, and passed through twenty-nine editions. In theology he was chiefly engaged in defense of the doctrine of Christ's twofold nature. We mention, Responsio ad Maledicum Francisci Stancari... de Trinitate et Mediatore Nostro Jesu Christo (1553): — De Aeterno Dei Filio Domino et Servatore Nostro Jesu Christo et. de Spiritu Sancto, etc. (1558): — Assertio Orthod. Doctr. de Duabus Naturis Christi, etc. (1575): — Scripta Veterum, de Una Persona et Duabus Naturis Christi, etc. (1571). The Commentarii in Exodum was published after his death, in 1584. The Confessio Helvetica of 1556, by Bullinger, has a preface by Simler. See Herzog, Real Encyklop. s.v.; Hoefer, Nouv. Biog. Generale, s.v.