Jam meta noctis transiit. [Morning.] Daniel, i., No. 4, and iv., p. 36, erroneously ascribes this to Hilary. It has not been traced earlier than to the Mozarabic Breviary of 1502, f. 2956, where it is in the Office of Aurora, i.e. the earliest of the hour services on week-days throughout the year.
Translated as:— Gone are the shades of night. By J. Brownlie, in his Hymns of the Early Church, 1896, p. 23, repeated in the Presbyterian Church Hymnary, 1898, No. 346, with lines 3-4 of the doxology altered. [Rev. James Mearns, M.A.]
--Excerpt from John Julian, Dictionary of Hymnology, New Supplement (1907)