Christi hodierna celebremus natalitia. [Christmas.] A sequence in the Mass of the sixth day after Christmas Day, whether it be a Sunday or not, in the Sarum Missal, and for the third Mass of Christmas Day, in the Hereford and York Missals. In the Hereford Missal the first line reads, "Christi hodierna pangimini omnes una." With the exception of the second verse, the intercisions and endings of the verses are in the letter a. The Sarum text is given in the Burntisland edition, 1867, col. 74; the York, in the Surtees Society reprint, vol. 59, p. 19; and the Hereford, in the reprint, 1874, p. 16. In the St. Gall manuscript, No. 614 (of the 10th century), it begins as in the Hereford Manuscript In the Bodleian manuscript, No. 775, f. 136 (written c. 1000), and in an 11th century Winchester manuscript now in Corpus Christi College, Cambridge (ms. 473), it begins with stanza ii. “Coelica resonent." Translated as:—
0 come, loud anthems let us sing, by E. H. Plumptre, written for and first published in the Hymnary, 1872, No. 135. Also given in Dean Plumptre's Things New and Old, 1884. Also translated as:—
Let us celebrate this day, Christ the Lord's nativity. C. B. Pearson. 1868. [Rev. James Mearns, M.A.]
--John Julian, Dictionary of Hymnology (1907)