Proper Psalms
From BiblePortal Wikipedia
Proper Psalms [1]
i.e. psalms adapted by their contents to the subjects of particular Sundays or festivals and holydays. St. Chrysostom refers to ancient prescription in this matter, and St. Augustine mentions as an old custom the use of Psalms 22 on Good Friday. Cassian informs us that Psalms 63 was sung at matins, and the 141st at evensong. St. Athanasius and St. Augustine appointed special psalms on certain occasions.
