Medieval Monastic Music Manuscripts

The Austrian Medieval Monastic Music Manuscripts Database allows free and universal access to complete and fragmentary manuscripts with musical notation written before c. 1600, kept at monastic libraries in Austria. Every manuscript is given in full-color reproduction, with a general description. Selected codices and fragments are fully indexed.
The A4M Database is part of the Cantus Index Network and is connected to other international medieval music databases by means of unique Cantus ID numbers. 

Augustinian Monastery Klosterneuburg 

With more than 270,000 volumes, the library of the Klosterneuburg Abbey is the largest private library in Austria. The core of the library consists of a medieval collection of 1,250 manuscripts and 860 incunabula (pre-1501 printed books). Most of these volumes were manufactured and painted in the scriptorium of the monastery, but some were purchased from Italy or France in the High or the Late Middle Ages. 

A collection of liturgical codices and fragments with notation forms an important part of the library. Most of these manuscripts document medieval Latin liturgical chant – cantus planus (plainchant). A smaller number of medieval materials consists of polyphonic sources.
Some of the complete manuscripts are accessible in Cantus: A Database for Latin Ecclesiastical Chant (https://cantus.uwaterloo.ca/; antiphonaries A-KN 1010, 1012, 1013, 1015, 1017, 1018, 589) and in the Mittelalterliche Handschriften in Österreich database (manuscripta.at; https://manuscripta.at/). Fragmentary materials are now part of a separate collection of fragments (shelfmark Fragm.), or form part of the binding or front or back pastedown of the other mediaeval manuscripts (shelfmark CCl.), incunabula, or younger prints of the library, or, in some cases, of the cover of the official protocols of the archive of the abbey.
The medieval sheet music dates back to a period between the eleventh century and the early sixteenth century, and its vast majority originated directly in Klosterneuburg.

More about history (https://www.stift-klosterneuburg.at/en/monastery-and-order/history/)