BIBLIOGRAPHY.--A comprehensive survey of the sources and literature for the history of Gregory VII. is given by C. Mirbt, s.v. "Gregor VII." in Herzog-Hauck, _Realencyklopadie_, 3rd ed. vol. vii. pp. 96 sqq. The main source for the reign of Gregory consists of his letters and decrees, the greater part of which are collected in the _Registrum_ (ed. P. Jaffe, _Bibliotheca rerum Germanicarum_, ii., Berlin, 1865). The letters preserved in addition to this official collection are also reprinted by Jaffe under the title of _Epistolae collectae_. The _Dictatus Papae_--a list of twenty-seven short sentences on the rights of the pope,--which is given in the _Registrum_, is not the work of Gregory VII., but should probably be ascribed to Cardinal Deusdedit. Further: A. Potthast, _Bibliotheca historica medii aevi_, i. (2nd ed., Berlin, 1896), pp. 541 sq., ii. 1351; P. Jaffe, _Regesta pontificum_ (2nd ed., 1865), tome i. pp. 594-649, Nr. 4771-5313, tome ii. p. 751. The most important letters and decrees of Gregory VII. are reprinted by C. Mirbt, _Quellen zur Geschichte des Papsttums_ (2nd ed., Tubingen, 1901), Nr. 183 sqq., pp. 100 sqq. The oldest life of Gregory is that by Paul von Bermried, reprinted, e.g. by Watterich, _Vitae pontificum_, i. 474-546. Among the historians the following are of especial importance: Berthold, Bernold, Lambert von Hersfeld, Bruno, Marianus Scotus, Leo of Ostia, Peter of Marte Cassino, Sigebert of Gembloux, Hugo of Flavigny, Arnulph and Landulf of Milan, Donizo--their works being reprinted in the section "Scriptores" in the _Monumenta Germaniae historica_, vols. v., vi., vii., viii., xii. The struggles which broke out under Gregory VII. and were partially continued in the subsequent decades gave rise to a pamphlet literature which is of extreme importance for their internal history. The extant materials vary greatly in extent, and display much diversity from the literary-historical point of view. Most of them are printed in the _Monumenta Germaniae_, under the title, _Libelli de lite imperatorum et pontificum saeculis XI. et XII. conscripti_, tome i. (Hanover, 1891), tome ii. (1892), tome iii. (1897). The scientific investigation of the Gregorian age has received enormous benefit from the critical editions of the sources in the _Monumenta Germaniae_, so that the old literature is for the most part antiquated. This is true even of the great monograph on this pope--A. F. Gfrorer, _Papst Gregorius VII. und sein Zeitalter_ (7 vols., Schaffhausen, 1859-1861), which must be used with extreme caution. The present state of criticism is represented by the following works: G. Meyer von Knonau, _Jahrbucher des deutschen Reichs unter Heinrich IV. und Heinrich V._, vol. i. (Leipzig, 1890), ii. (1894), iii. (1900), iv. (1903); W. Martens, _Gregor VII., sein Leben und Werken_ (2 vols., Leipzig, 1904); C. Mirbt, _Die Publizistik im Zeitalter Gregors VII._