Hymns written in iambic dimeter form, whether by Saint Ambrose, or his contemporaries, c374Those attributed to Saint Ambrose were syllabic in form and simple in rhythm, but the texts underwent many subsequent rhythmical and melodic changes. A comparison of various codices from different centuries made possible the restorations of Guido Dreves, 1893. The chants now used in the Ambrosian, or Milanese, Rite, originated for the most part in later liturgical developments.