Joseph Hergenröther (15 September 1824 – 3 October 1890) was a German Church historian and canonist, and the first Cardinal-Prefect of the Vatican Archive.

Biography Born in Würzburg, he was the second son of Johann Jacob Hergenröther, professor of medicine in the University of Würzburg. In 1842, Hergenröther completed with notable success his gymnasium course in his native town, and entered the University of Würzburg to take up a two-year course of philosophical studies, to which he added certain branches of theology. His historical tendencies exhibited themselves at this early age in a dramatic poem entitled Papst Gregor VII (Würzburg, 1841).

Bishop von Stahl took an interest in him, and in 1844 sent him to the Collegium Germanicum et Hungaricum in Rome, whither he had already sent Heinrich Joseph Dominicus Denzinger and Franz Hettinger. Among his scholarly teachers were Giovanni Perrone and Carlo Passaglia in doctrinal theology, Tomei in moral theology, Antonio Ballerini in church history, Francis Xavier Patrizi in Scriptural exegesis, and Marzio in canon law.

The political troubles of 1848 prevented the completion of his theological studies at the Collegium Germanicum et Hungaricum in Rome; he was ordained to the priesthood on 28 March of that year, and returned to Würzburg, where he pursued his ecclesiastical preparation for another year. In 1849, he was appointed chaplain at Zellingen, and for some time devoted himself to the duties of his office. In 1849, he successfully defended for the degree of doctor of theology before the Ludwig-Maximilians-Universität München with his dissertation on a treatise on the Trinitarian teaching of St. Gregory Nazianzen (Die Lehre von der göttlichen Dreieinigkeit nach d. heil. Gregor von Nazianz, Ratisbon, 1850). The qualities of the young doctor induced the theological faculty of the Ludwig-Maximilians-Universität München to offer him a place as instructor (privatdozent) in theology, which he accepted. Following ancient usage, he justified the confidence of the Ludwig-Maximilians-Universität München by a printed thesis (Habilitationschrift) on the later Protestant theories of the origins of the Catholic Church (De catholicæ ecclesiæ primordiis recentiorum Protestantium systemata expenduntur, Ratisbon, 1851). Henceforth, he devoted himself without reserve to his professorial duties.

In 1852, he was called to the University of Würzburg as professor extraordinary of canon law and church history; after three years he was promoted to the full possession of that chair in 1855. To his other duties, he added the teaching of patrology. In those years, the University of Würzburg rejoiced in the possession of such theologians as Hettinger, Denzinger, Hähnlein, and Hergenröther.

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".Patrologia Graeca, CI-CIV. 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 1864 in Munich, 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 Krumbacher, the historian of Byzantine literature, says that the work cannot be surpassed. In these volumes Hergenröther laid here in minute detail the origins of the Byzantine Church, its development since the fourth century, and after the death of Photius until the completion of the schism in the twelfth and thirteenth centuries.

While professor of canon law at Würzburg, Hergenröther published several important historico-canonical essays on such subjects as early ecclesiastical reordinations (Ester, Vierteljahrsch. f. kath. Theol., 1862), the canonical relations of the various rites in the Catholic Church (Archiv f. kath. Kirchenrecht, 1862), the politico-ecclesiastical relations of Spain and the Holy See (ibid., 1863–66), and the canon law of the Greeks to the end of the ninth century (ibid., 1870). His interest in the ecclesiastical vicissitudes of his own day was manifested by valuable essays on the States of the Church after the French Revolution (Hist.-polit. Blätter, 1859), spirit of the age (Zeitgeist) and papal sovereignty (Der Katholik, 1861), and the Franco-Sardinian Treaty (Frankfort, 1865). Among his historico-apologetic essays are his treatises on the errors condemned by the Holy See in the Encyclical (Syllabus) of 8 December 1864 (in the Chilianeum, 1865), the veneration of the Blessed Virgin in the first ten centuries of the Christian Era (Münster, 1870).

He was a regular contributor of similar but briefer articles to the Würzburg periodicals, "Die katholische Wochenschrift" and the "Chilianeum". Hergenröther was constantly engaged in attempting to develop a genuine Catholic sentiment and truly Christian life among the faithful. He preached frequently, and was always a welcome speaker at the general assemblies of the German Catholic associations (Vereine; 1863–77). For the Fulda meeting of the Prussian bishops (1870) he prepared an exhaustive historical study on the spoliation of the Papal States, in which he developed at length the arguments for the temporal power of the papacy.

At the Ludwig-Maximilians-Universität München, he gained the reputation of being one of the most learned theologians on the Ultramontane side of the Infallibility question, which had begun to be discussed; and in 1868 he was sent to Rome to arrange the proceedings of the Vatican Council. Together with some other Catholics, Hergenröther deplored the attitude that certain Catholic theologians assumed from about 1860, in particular that of the celebrated historian Döllinger. The latter's work Kirche und Kirchen, Papsttum und Kirchenstaat (1861) was criticized by Hergenröther in "Der Katholik". At the Munich meeting of Catholic savants (1863), Hergenröther was one of the eight who sent in a written protest against the opening discourse of Döllinger on the past and present of Catholic theology. Among the other signers were Heinrich Moufang von Schäzler, Paul Leopold Haffner, Franz Hettinger, and Matthias Joseph Scheeben. Hergenröther was soon called on to answer the pamphlet of Dr. Friedrich Bernhard Ferdinand Michelis, Kirche oder Partei? Ein offenes u. freies Wort an den deutschen Episkopat (Church or Faction? A Frank Address to the German Episcopate), in which this writer attacked violently the "Mainz" and the "Roman" theologians. Hergenröther's answer appeared in the "Chilianeum" (1865) under the title of Kirche u. nicht Partei. Eine Antwort auf die jüngste Broschüre des Herrn Dr. Fr. Michelis (Church and not Faction: an Answer to the latest Brochure of Dr. Michelis). In the same review (1863) Hergenröther had written a critical account of the latest efforts of Western Catholics for ecclesiastical reunion with the Oriental Churches.

The opening of the Vatican Council (1870) brought to a head the domestic conflict in Germany. Hergenröther was the foremost defender of the council and its decrees; as early as 1868 he had been appointed, with Hettinger, consultor for the preparation of the council's work and had taken up his residence at Rome. His knowledge of ecclesiastical history, canon law, and Catholic dogma made him a valuable co-labourer in the many careful and detailed preliminary meetings of the council commission. In the meantime he prepared, with Hettinger, and published in the "Chilianeum" (1869) a memorial of the theological faculty of Würzburg in reply to five questions, submitted by the Bavarian Government, concerning the approaching council. He also published (Der Katholik, 1871) another outlined memorial concerning the Vatican Council, in reply to eleven questions submitted by the Bavarian Minister of Worship to the theological and law faculties of Würzburg. This memorial, though projected, was never formally called for by the Government.

The opposition to the Vatican Council reached its acme in the work Der Papst und das Concil, by "Janus" (Döllinger). In the same year (1869) Hergenröther prepared his "Anti-Janus", an historico-theological critique (Freiburg, 1870). He also published a number of small brochures in favour of the council and against Döllinger, e. g. "Die Irrthümer logischer Censor" (Freiburg, 1870), and a critique of Dr. Döllinger's declaration of 28 March 1871 (Freiburg, 1871). His pen was also active in the "Historisch-politische Blätter", where he published (1870) a series of articles on the "Allgemeine Zeitung" and its letters from the council, on papal infallibility before the Vatican Council, and on ancient Gallicans and modern Appellants. In 1871 he published the solid study "Das unfehlbare Lehrant des Papstes" [The Infallible Magisterium (teaching office) of the pope, Passau, 1871]. These grave and exhausting labours were crowned and partially summarized by a new work, Katholische Kirche u. christlicher Staat in ihrer geschichtlichen Entwicklung u. in Beziehung auf die Gegenwart (The Catholic Church and the Christian State, in their historical development and their relations to the present), together with an "Anti-Janus vindicatus" (Freiburg, 1872, 2nd annotated ed., Freiburg, 1876). The former is a thesaurus of information concerning politico-ecclesiastical conflicts of the past, and is marked throughout by an uncompromising tone. It was translated into Italian (Pavia, 1877) and into English (London, 1876; Baltimore, 1889).