It comprises (like the hymns for Terce and Sext) only two stanzas of iambic dimeters together with a doxology, varying according to the feast or season.
As in the hymns for Prime, Sext and Compline, the theme is found in the steady march of the sun, that defines the periods of the day (and provided the basis of Roman and monastic chronology): which translates (not literally, nor strictly by verse): Who mark'st the day-hours as they run by steady marches of the sun'.
The moral application is, as usual, made in the following stanza: The authorship of the hymns for Terce, Sext and None is now ascribed only very doubtfully to St. Ambrose.
of the cycle give for these hours, for the remainder of the year, the hymns: "Certum tenentes ordinem", "Dicamus laudes Domino", "Perfectum trinum numerum"; while other MSS.
give as variants for Lent: "Dei fide qua vivimus", "Meridie orandum est", "Sic ter quaternis trahitur".