Nicene and Post-Nicene Fathers: Series II/Volume XI/John Cassian/The Twelve Books/Book III/Chapter 6

Chapter VI.

How no change was made by the Elders in the ancient system of Psalms when the Mattin office was instituted.

this too we ought to know, viz., that no change was made in the ancient arrangement of Psalms by our Elders who decided that this Mattin service should be added; but that office was always celebrated in their nocturnal assemblies according to the same order as it had been before. For the hymns which in this country they used at the Mattin service at the close of the nocturnal vigils, which they are accustomed to finish after the cock-crowing and before dawn, these they still sing in like manner; viz., Ps. 148, beginning &#8220;O praise the Lord from heaven,&#8221; and the rest which follow; but the 50th Psalm and the 62nd, and the 89th have, we know, been assigned to this new service. Lastly, throughout Italy at this day, when the Mattin hymns are ended, the 50th Psalm is sung in all the churches, which I have no doubt can only have been derived from this source.