In the Middle Ages there was a prominent scriptorium here where lots of codices were copied; some of them were even illuminated. Nowadays the museum holds 155 codices that have come to our day in a good state of preservation, in addition to the 800 documents in parchment paper, around 300 incunabula and 1055 old rare volumes from 16th, 17th and 18th centuries. 

 

Due to the great amount of literary jewels kept here, towards 1534 the construction of this library was commissioned to Juan de Badajoz ‘el Mozo’, (‘the Young one’) and it is considered as one of the best Renaissance samples of the city of León, with access from a monumental doorway. 

 

The room is sheltered by a central oval dome decorated with prophets, skulls, flowers and pendants. The medallions stand out on the pendentives and the wall has a wide impost or fascia all along where the famous Isidorian litany can be seen in golden letters.

 

Among the volumes in this legacy there are several priceless works: 

 

The jewel in the crown is the Visigothic-Mozarabic Bible or Codex Biblicus Legionensis (960). Apart from its ancient dating, this Bible is remarkable from the artistic point of view because of the abundance and quality of its miniatures, rich in chromaticism and expressiveness and also due to its importance as historical document representing the social life of Christian Spain in the 10th century as it could be traced in palaces and temples, trousseaus, civilian and war clothes, and so on. Today it is regarded by experts as the biblical codex of Mozarabic liturgy par excellence.

 

The Bible of 1162 provides sound evidence of the influential medieval scriptorium housed in this place, since this Bible was written in the monastery of San Isidoro using the Bible of 960 as its model. Thus, the miniatures and biblical stories are copied from it although adapting them to what were considered, by then, the new trends in building, trousseau, clothes and weapons; consequently, the evolution of the style in the treatment of color and the quality of the drawing can be easily appreciated. 

 

The Codices of Santo Martino (St. Martin), an illustrious canon of this house who, with seven scribes under his direction, was responsible for a series of treaties that can be placed within the style of 1200. They are a collection of volumes versed in the moral edification of canons, as well as in theological and monastic questions. From the artistic point of view, it is worth highlighting its richly ornamented initials together with characters that stand out due to the use of color and the quality of its drawing, as it is the case with San Isidoro and with the portrait of the author himself.

 

The last miniatures preserved in this museum are late-Gothic and Baroque hymnals used as choir books for the canonical hours; they comprise from matins to compline and the monks daily place them on the lectern in the center of the choir. Among them, a 15th-century hymnbook deserves special attention: it contains Advent, Epiphany and Christmas chants, being particularly outstanding the later, that of Christmas, as a result of its Nativity scene, illuminated by Nicolás Francés (ca. 1450), also creator of the altarpiece of the Cathedral of León.