The Codex Justiniani, called the 'Digest' or 'Pandects', goes back to 534 when the Emperor Justinian had imperial decisions and enactments compiled as part of his programme to codify Roman law. When law began to be studied in western European universities, starting with Bologna in the 11th century, the 'Pandects' became valued as basic legal texts. The need for huge textbooks like the Codex Justiniani fuelled the development of workshops to produce books outside of monasteries. In England, Oxford became a manuscript producing centre, turning out books like this one, which was owned by Merton College. The daunting appearance of this page results from its dense marginal and interlinear glosses. It is a good example of the sophisticated page layout developed in the middle ages for glossed theological and legal textbooks. The 'Pandects' proper is written in larger script in the two columns in the middle of the page, with wide margins left all around for scribes and masters to insert the glosses. Most of the glosses are contemporary with the writing in the centre, but others were added later by masters or students who used the book. Ideally the glosses are written next to the relevant bit of the main text, but in some places (lower margin) dotted lines connect up a long gloss. The portrait of an emperor, shown as a medieval king, heads the section beginning on this page, and imaginary animals stand guard in the margin to signal the beginnings of subsections.