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 this manuscript has an inscription stating that it belonged to the cloister of Rochester cathedral. This page has the beginning of Isaiah 6, marked by the large first letter, a conventional way of showing divisions in books. On this page, most of he explanatory notes run down the right side of the page, and the notes on individual words are written between the lines.