Medieval monasteries produced a large quantity of high-quality literature, but they also produced diagrams too. The Thorney Computus contains a world map, a diagram of the relationship between the four elements (earth, water, fire and air) and complex tables used to calculate the dates for Easter and other religious festivals important to the monastic community using a lunar calendar. The detail and complexity is outstanding, which is why it now resides in St John's College, Oxford University.
This document is usually attributed to the original work of Byrhtferth of Ramsey Abbey, the Ramsey Computus predating that of Thorney. Dates calculated in the work relate to the 10th and 11th centuries when Byrhtferth was alive, suggesting this was created as an exercise, or as training for practising monks.
The Peterborough Computus is almost identical and considered a sibling manuscript, it being later in date.
Medieval monasteries produced a large quantity of high-quality literature,…