Hergenröther was often honoured by election to the office of dean of his faculty, and occasionally to the University Senate; the latter office he never held after 1871, because of his opposition to Ignaz von Döllinger. For a similar reason he was never chosen to be rector of the university. Until 1869 Hergenröther was occupied as teacher and writer, chiefly with early Christian and Byzantine ecclesiastical history. The discovery (1851) of the Greek Christian text known as the Philosophoúmena led him to examine its disputed authorship in a series of studies in the Tübinger Theol. Quartalschrift (1852) and in the supplementary volume (1856) to the first edition of the Kirchenlexikon of Heinrich Joseph Wetzer and Benedict Welte. He again defended the authorship of Hippolytus in the Œsterreichische Vierteljahrschrift f. kath. Theol. (1863). Hergenröther was especially interested in the career of Photius and in the origins of the Greek Schism, and kept up continuous research in the principal libraries for manuscripts of the works of Photius, in order to exhibit the original materials in as perfect a text as could be established. This led to the publication (Ratisbon, 1857) of the work, Photii Constantinopolitani Liber de Spiritus Sancti mystagogia. He contributed essays on the same work and on the Amphilochia of Photius to the Tüb. Theol. Quartalschrift (1858). In 1860 appeared at Paris the Migne edition of "Photius". It offered many textual emendations that were owing to Hergenröther, particularly in the "Amphilochia"; it was against his will that his earlier edition of the "Liber de Sp. Sancti mystagogia" was reprinted by Migne. When Aloys Pichler's work on the history of the separation of the Eastern and Western Churches appeared (Munich, 1864), Hergenröther was prepared to criticize it in the most thorough manner, which he did in a series of studies in a Würzburg theological periodical, the "Chilianeum" (1864–65), and in the "Archiv. f. kath. Kirchenrecht" (1864–65). The results of his twelve years of research in the history of the Greek Schism appeared finally in the classical work, Photius Patriarch von Constantinopel, sein Leben, seine Schriften, und das griechische Schisma (3 vols., Ratisbon, 1867–69). An additional volume bears the title: Monumenta Græca ad Photium ejusque historiam pertinentia (Ratisbon). In this monumental work it is difficult to say whether the palm belongs to the author's extensive knowledge of all the manuscript material, to his profound erudition, or to his calm objective attitude. Karl