COMES (Liber Comitis, Liber Comicus). - The C. must originally have been simply a book of private spiritual reading, containing a collection of texts from Holy Scripture and from other devout authors. This is precisely what the word c. means, that is, "companion," and it was used for persons and for things. For example, the "paidagogos," or educator of the young, was called comes by the Romans, because he had to accompany the boy entrusted to him everywhere. Likewise the book that was to accompany the Christian through his life, his spiritual "vademecum," was called C. (Cf. C. Du Cange, Glossarium ad scriptores mediae et infimae latinitatis, new ed., Paris 1937, p. 422).
But the word C. soon came to acquire a particular technical sense in the field of liturgy, and, in this sense, it designated the book containing the passages of Holy Scripture to be read at Mass during the liturgical year. The best-known collection that passed under this name is the one that medieval liturgists attribute to St. Jerome, and which Alcuin reworked by order of Charlemagne (v. CARLOMAGNO, riforma liturgica).
The first printed editions of this C., such as J. Pamelius, Liturgicon ecclesiae latinae, Cologne 1571, p. 1 ff.; G. M. Tomasi, Opera omnia, ed. A. F. Vezzosi, V, Rome 1750, pp. 297 ff.; PL 30, 487-532 etc., reported only the incipit and the explicit of the individual passages, since these are known to all; from this manner of publication, however, there arose, among not a few later authors, the idea that the word c. designated exclusively an "index" of the passages, that is, a "capitulare," but this is erroneous. The C. was a book with the complete text of the individual passages, as is clear from the recent editions, such as, for example, that of Alcuin's C., edited by A. Wilmart, Le lectionnaire d'Alcuin, Rome 1937 (offprint from the Ephemerides liturgicae). It must be noted, however, that, besides the term c., there existed many other designations for the various types of books containing the passages for Mass (v. EPISTOLARIO; EVANGELIARIO; LEZIONARIO).