Except for service books such as Psalters and Missals, manuscripts like this one--books of the Bible accompanied by extensive glosses--were perhaps the most numerous type of manuscript produced during the 12th century. They encompass not only the biblical text, but a careful selection of the interpretations of a variety of the Church's greatest early thinkers and writers, arranged adjacent to the passage being interpreted. This manuscript was owned in the Middle Ages by the library of York Cathedral. Following a general prologue to the Gospels, the common prologue to the Gospel of Matthew is introduced by a gold initial with coloured penwork infill and marginal extensions. The text of the prologue itself (commonly attributed to St. Jerome) is written in large script on alternate lines, while the gloss is written between these lines in smaller script.