Six hymns which have come down to us are attributed with certainty to this gifted saint. They are the _Deus creator omnium_, _Jam surgit hora tertia_, _Æterne rerum conditor_, _Veni redemptor gentium_, _Illuxit orbi_ _jam dies_, and _Bis ternas horas explicans_. Probably also he was the author of _O lux beata Trinitas_, _Hic est dies verus Dei_, _Splendor paternæ gloriæ_, and _Æterna Christi munera_. The melodic forms of these hymns are borrowed directly from the Greeks and Romans. Stripped of their melismas their primitive contours are easily recognizable, and their structure is thoroughly in accord with the modal theory of the classic Greeks. All of these hymns which seem to be the most ancient belong to one of the principal kitharœdic modes--the Dorian, Iastian, or Æolian. The Ambrosian hymns in the Dorian mode have the same melodic texture as the hymn to Helios and the main part of the song to the Muse (see pp. 126-127 above). Hymns after the manner of Ambrose in the Iastian and Æolian modes are frequent in the Catholic hymnody.[49] The Græco-Roman complexion of the Ambrosian hymns is still further evident in their metrical form. 'The old ecclesiastical hymns composed in iambic dimeters and ascribed to Bishop Ambrose,’ says Riemann, 'are still firmly founded upon the antique art, as they respect absolutely the quantity of the syllables and introduce long syllables and short ones only where it is in accordance with the laws of classic poetry.’[50] The eight syllable iambi of the Ambrosian verse became extremely popular in ecclesiastical hymnody, and the Breviary, as it is to-day, contains many hymns in that measure. But this was not the only metrical form of classic Rome that became incorporated in the liturgy of the Church. Vanantius Fortunatus in the sixth century introduced the trochaic tetrameter, which was a favorite popular verse among the ancient Romans, and still survives in the rhythm of the Roman _saltarello_ and the Neapolitan _tarantella_. The elegant Sapphic strophe, so dear to Latin lyricists, made its appearance subsequent to the Carlovingian epoch. As long as Latin prosody remained dominant the ecclesiastical hymns were more or less metrical, but as literary Latin passed into desuetude these chants lost their isochronous rhythm. At the beginning of the eighth century the vogue of metrical verse had already passed. With it passed, too, the classic melopæia which had gradually become enriched by accessory inflexions.[51]