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 manuscript has the sophisticated layout that was developed to present glossed textbooks (textbooks with explanatory notes in the margins and between the lines): the main text in the centre, arranged in two columns, with a wide margin all around to hold the glosses. The layout enabled scribes and masters to place the glosses beside the relevant bit of text. The mermaid, majestic bird and hedgehog draw attention to the beginnings of subsections (with their titles written in red), but it is easy to imagine them providing some relief from the heavy going of the massive blocks of writing.