The study of the ecclesiastical year was considerably advanced by the labours of Adrien Baillet, born in 1649, in the diocese of Beauvais († 1706), parish priest of a small country living at Baumont and librarian to M. de Lamoignon; he was entirely devoted to the pursuit of knowledge, and scarcely ever allowed himself any relaxation. He composed a great work worthy of ranking alongside the labours of Tillemont, to whom he is closely related in spirit. The course of his historical treatment of the subject is considerably obscured by the superabundance of biographical matter. Two valuable monographs were published by Prosper Lambertini (Pope Benedict XIV.) when bishop of Bologna, which treat in a masterly manner of the feasts of our Lord and of our Lady respectively. Finally, the learned priest of Bilk, near Düsseldorf, Fr. Ant. Binterim († 1855) dealt with this subject in one volume of his _Denkwürdigkeiten_. He treats in the first place of the observance of Sunday, then of the Sundays of the Church’s year in general, and finally of the movable and immovable feasts. Of these he naturally deals only with the most important, following the order of the calendar, by which arrangement Christmas comes last. The author of this book commenced his researches by a comparative study of the martyrologies, calendars, annals, and works dealing with the computation of time, and then set to work upon the historical and liturgical material which he had before him from the point of vantage thus obtained. The fortunate circumstance that the most of the works required for this branch of study are contained in Migne’s collection, renders the labour of comparison possible, and frequently brings remarkable parallels to light. APPENDIX I (p. 16) According to the existing Roman Calendar, feasts are classed as follows:— DUPLICIA PRIMÆ CLASSIS. _Nativitas Domini, Epiphania, Annunciatio, Pascha cum tribus antecedentibus et duobus sequentibus diebus, Ascensio Domini, Pentecoste cum duobus sequentibus diebus, festum Corporis Christi, festum SS. Cordis Jesu, festum S. Joseph sponsi B.M.V., Nativitas Joannis Bapt., festum SS. App. Petri et Pauli, Assumptio B.M.V., festum Immaculatæ Conceptionis B.M.V., festum Omnium Sanctorum, Dedicatio propriæ ecclesiæ, Patronus vel titulus ecclesiæ._ DUPLICIA SECUNDÆ CLASSIS. _Circumcisio Domini, festum SS. Nominis Jesu, festum SS. Trinitatis, festum Pretiosissimi Sanguinis D. N. J. Chr., Inventio Crucis, Purificatio, Visitatio, Nativitas B.M.V., Sollemnitas S. Rosarii, Dedicatio Michælis Arch., festum Patrocinii S. Joseph sponsi B.M.V., Natales Apostolorum et festa Evangelistarum, festum S. Stephani, Protomartyris, SS. Innocentium, S. Laurentii, S. Annæ matris B.M.V., S. Joachim patris B.M.V._