The rich medieval abbeys possessed important libraries which were constituated and enriched by the activities of the monks through the manuscripts. In the 13th century Moissac had a library so rich that it regularly lent works to other benedictine abbeys.

The library is conserved in the main by the National Library of France. Works can be found in libraries all over the world notably a magnificant illumination of a brevaire from the 15th century which is the property of the Pierpont Morgan Library in New York.

The content of the library is known due to a thesis carried out by L'Ecole des Chartes.

In addition, two ancient catalogues exist. They indicate the type of works filed in the L'armarium and the tecta bibliorum at the end of the 11th century. We can read : "All the divine books (libri divini) contained by the Armarium amount to 60 with the exception of those unheard of.....and the books relating to Art (libri arte) which number 11... ".
There are also books placed in the choir and the sacrisist.

A simple list of works :
- the Bible in 4 volumes
- dthe manuscripts of the Fathers of the Church such as saint Jerome (7 volumes), saint Augustin (17 volumes ), and saint Ambroise (4 volumes)
- historical manuscripts including "La guerre des Juifs " writen by Flavius Josèphe, a theological work by Rufin de Aquilée (4th century), "L'histoire universelle " by Paul Orose from the beginning of the fifth century, and a work by the scholar Cassiodore from the sixth century.

The decoration of the manuscripts was carried out by an illuminator who could only begin once the manuscripts had been written.
The decoration was used at the beginning of each chapter or important phrase as a method of referencing. This decoration is indicative of the Roman illumination.
In Moissac, the motifs are very simple during the early period (10th and beginning of the 11th century), however they evolve during time, vegetable elements bring out the animal representations which are sometimes fanciful. With time, these develop into scenes from a story. The letter has been used as a support for a picture.

These iconographical documents ( colour slides), are available for free consultation by all visitors to the cloister through a precise repertoire
With the documentation on the illuminations originating in Moissac can be added other illuminations from Limoges, Albi, Cluny, Sant-Yrieix...

Various works on the illuminations and fascimiles of prestigious works including; Lectionnaire du Vatican, Psautier d'Utrecht, etc... are also available at the Centre. They give an insight into the reality of the medieval manuscript.