IDELER, LUDWIG. _Handbuch der mathematischen und technischen Chronologie._ 8vo. 2 vols. Berlin, 1825-26. [Ideler was Royal Astronomer and Professor in the University of Berlin. His discussion of the Easter cycles cannot be dispensed with. This and his account of the computation of time in the Christian Church will be found in Vol. 2 (pp. 175-470). The Gregorian reform is well dealt with.] KELLNER, K. A. HEINRICH. _Heortology: a history of the Christian Festivals from their origin to the present day._ Translated from the second German edition. 8vo. London, 1908. [Dr Kellner is Professor of Catholic Theology in the University of Bonn. An interesting and useful volume, though occasionally exhibiting, as is not unnatural, marked ecclesiastical predilections. It contains prefixed a useful bibliography.] LIETZMANN, H. _Die drei ältesten Martyrologien._ E. tr. 8vo. Cambridge, 1904. [This little pamphlet of 16 pages exhibits conveniently the texts of (1) what is variously known as the Bucherian, or Liberian, or Philocalian Martyrology, (2) The Martyrology of Carthage, and (3) Wright’s Syrian Martyrology.] MACLEAN, ARTHUR JOHN (Bishop of Moray). The article ‘Calendar, the Christian’ in Hastings’ _Dictionary of Christ and the Gospels_ [admirable, generally, for the early period.] MACLEAN, ARTHUR JOHN (Bishop of Moray). _East Syrian Daily Offices._ London, 8vo., 1894. [An appendix deals with the Kalendar of the modern Nestorians (Assyrian Christians).] NEALE, JOHN MASON. _A History of the Holy Eastern Church. General Introduction._ London, 8vo., 1850. [Vol. II. gives information at considerable length on the Kalendars of the Byzantine, Russian, Armenian, and Ethiopic Churches.] NILLES, NICOLAUS. _Kalendarium Manuale utriusque Ecclesiae Orientalis et Occidentalis, academiis clericorum accommodatum._ 2 tom. 8vo. Oeniponte, 1896, 1897. [N. Nilles, S.J., Professor in the University of Innsbruck, deals mainly in these volumes with the ecclesiastical year in Eastern Churches.] QUENTIN, HENRI. _Les Martyrologes historiques du moyen age, étude sur la formation du Martyrologe romain._ 8vo. Paris, 1907. SAXONY, MAXIMILIAN, PRINCE OF. _Praelectiones de Liturgiis Orientalibus._ Tom. I. 8vo. Friburgi Brisgoviae, 1908. [This volume is mainly concerned with the Kalendars and Liturgical Year of the Greek and Slavonic Churches. It is lucid and interesting.] SEABURY, SAMUEL, D.D. _The Theory and Use of the Church Calendar in the measurement and distribution of Time; being an account of the origin and use of the Calendar; of its reformation from the Old to the New Style; and of its adaptation to the use of the English Church by the British Parliament under George II._ 8vo. New York, 1872. [Excellent on the restricted subject with which it deals. It does not deal with Christian Festivals beyond the question of the determination of Easter, but is largely concerned with matters of technical chronology, the ancient cycles, golden numbers, epacts, etc.]