Of much greater scholarly merit is the Geschichte der religiösen Aufklärung im Mittelalter, vom Ende des achten Jahrhunderts bis zum Anfange des vierzehnten, by Hermann Reuter (1875, 1877). This is at once learned, judicious, and impartial. Its definition of "Aufklärung" is substantially in agreement with the working definition of Freethought given above. Among other surveys of periods of innovating thought, as distinguished from histories of ecclesiastical heresy, or histories of "religious" or theological thought which only incidentally deal with heterodox opinion, should be noted the careful Geschichte des englischen Deismus of G. F. Lechler (1841); the slighter sketch of E. Sayous, Les déistes anglais et le Christianisme (1882); the somewhat diffuse work of Cesare Cantù, Gli eretici d'Italia (3 tom. 1865-67); the very intelligent study of Felice Tocco, L'Eresia nel medio evo (1884); Schmidt's Histoire des Cathares (2 tom. 1849); Chr. U. Hahn's learned Geschichte der Ketzer im Mittelalter (3 Bde. 1845-50); and the valuable research of F. T. Perrens, Les Libertins en France au xviie siècle (1896). A similar scholarly research for the eighteenth century in France is still lacking, and the many monographs on the more famous freethinkers leave a good deal of literary history in obscurity. Such a research has been very painstakingly made for England in the late Sir Leslie Stephen's History of English Thought in the Eighteenth Century (2 vols., 2nd ed., 1881), which, however, ignores scientific thought. One of the best monographs of the kind is La Critique des traditions religieuses chez les Grecs, des origines au temps de Plutarque, by Professor Paul Decharme (1904), a survey at once scholarly and attractive. The brilliant treatise of Mr. F. M. Cornford, From Religion to Philosophy (1912), sketches on more speculative lines the beginnings of Greek rationalism in Ionia. The Geschichte des Monismus im Altertum of Prof. Dr. A. Drews (1913) is a wide survey, of great synthetic value.