One of the tasks of medieval Christian writers was to explain the Old Testament in terms of Christianity. A tradition of explanatory notes developed to help theologians and students in their biblical studies. Sometimes Bibles copied especially for theological study were given accompanying commentary surrounding the biblical text in a frame-like arrangement and with notes on particular words written between the lines. These became standardised over the course of the middle ages. This copy of the Book of Isaiah shows the typical arrangement of the pages of books with these standardised explanatory notes, or the 'Glossa ordinaria'. The first page of the manuscript begins the Book of Isaia with a large illuminated initial, its sumptuousness expressing the high value which was placed on the work of the theologian. In the lower margin, the inscription says that the manuscript belonged to the cloister of Rochester cathedral under the authority of Paul, the prior ("Liber de claustro Roffensi [Rochester] per Paulum priorem").