Medieval psalters were made to be used either for personal devotion or in church services, including the offices or daily cycle of prayers recited by monks. The Glenorchy Psalter was used in a monastery in Argyll, in Scotland, before the Reformation, but by the first quarter of the 16th century it was owned by the 3rd earl of Glenorchy, Colin Campbell. Its calendar, an aid to the manuscript's users in planning prayers and readings for services, lists many saints who were revered in western Scotland. This page was inscribed in the 16th through 19th centuries with various identifying marks. There are old press-marks, "Shelfe 7. numb. 26" (16th century) ; "pr. 6. sh. 2 No 37" (18th-19th century), indicating its position in a library. Also, the bookplate of arms of the Earl of Breadalbane, 18th century, was added by a later owner. The back of the page carries a more interesting and important 16th-century inscription: "Liber Coline Campbell of Glenurquhay eiusdem Glenurquhay" ("Book of Colin Campbell of Glenurquhay"), probably Colin Campbell, 3rd Laird of Glenorchy, County Argy11, who died in 1523, the ancestor of the Earls and Marquises of Breadalbane.