Te Lucis Ante Terminum, the hymn at Compline in the Roman Breviary. The authorship of St. Ambrose, for which Pimont contends, is not admitted by the Benedictine editors or by Biraghi. The hymn is found in a hymnary in Irish script (described by Blume in his “Cursus”, etc.) of the eighth or early ninth century; but the classical prosody of its two stanzas (solita in the third line of the original text is the only exception) suggests a much earlier origin. In this hymnary it is assigned, together with the hymn “Christe qui lux es et dies”, to Compline. An earlier arrangement (as shown by the Rule of St. Caesarius of Arles, c. 502) coupled with the “Christe qui lux” the hymn “Christe precamur adnue”, and assigned both to the “twelfth hour” of the day for alternate recitation throughout the year. The later introduction of the “Te lucis” suggests a later origin, although in its simple dignity the hymn is not unworthy of the muse of St. Ambrose. The two hymns “Te lucis” and “Christe qui lux” did not maintain everywhere the same relative position; the latter was used in winter, the former in summer and on festivals; while many cathedrals and monasteries replaced the “Te lucis” by the “Christe qui lux” from the first Sunday of Lent to Passion Sunday or Holy Thursday—a custom followed by the Dominicans. The old Breviary of the Carthusians used the “Christe qui lux” throughout the year. The Roman Breviary assigns the “Te lucis” daily throughout the year, except from Holy Thursday (Te Lucis Ante Terminum, p. 2) to the Friday after Easter, inclusively. Merati, in his notes on Gavantus’s Thesaurus, says that it has always held, without variation, this place in the Roman Church. As it is sung daily, the Vatican Antiphonary (now passing through the press) gives it many plainsong settings for the varieties of season and rite (e.g. the nine melodies, pp. 117-121, 131, IT 4. J 356, 366).
H. T. HENRY