John Ernest, a learned theologian, was born at Königsberg in the year 1666. The perusal of the works of the fathers having inspired him with doubts as to some points of his creed, he explained them in a memoir addressed to the consistory of Sambia, and departed with the resolution of repairing to a city where he could make open profession of the Catholic religion. The elector of Brandenburg ordered three theologians to examine, each separately, the memoir of Grabe; and some of the reasons contained in the answers which they made to it having struck him forcibly, he demanded a safe conduct, which was granted him, and proceeded to Berlin to confer with Speuer, one of his adversaries. Upon some of the points in dispute they came to agree; but Grabe persisting in maintaining the necessity of the apostolical succession in the ministry, Speuer, having despaired of overcoming his conviction of this doctrine, counselled him to proceed to England, where he would find it established. Grabe followed this advice, and, having reached London, got himself ordained priest according to the English ritual; but not being able to bring his belief into accordance with that of the church which he had entered, he always preserved his private opinions touching the eucharist and consecration. Nevertheless, the regularity of his conduct, and his useful labours, recommended him to notice; he obtained some benefices; and Queen Anne granted him a pension, which he enjoyed till his death, which took place at London on the 13th of September 1711, in the forty-fifth year of his age. His works, which have obtained him the reputation of a learned and laborious man, but indifferent critic, are, 1. Specilegium SS. Patrum et Hæriticum seculi post Christi natum primi, secundi, tertii, Oxford, 1698 and 1699, in 8vo; 2. S. Irenæi episcopi Lugdunensis adversus haereses libri v, Oxford, 1702, in folio; 3. Vetus Testamentum juxta Septuaginta Interpretes, Oxford, 1707, 1719, 1720, and 1729, in folio; 4. Liturgia Graeca, Hague, 1715, in 8vo; 5. De forma consecrationis Eucharistiae, hoc est, Defensio Ecclesiae Graecæ.