In older institutions, simpler numbering systems are sometimes maintained alongside, or incorporated within, newer systems. Where the objects are unique, institutions normally need to retain the original number in some form as it will have been used in old references that are still of use in scholarship. In particular, collections of
manuscripts use the prefix "MS", and many well known manuscripts are known by their old MS numbers, often incorporating a prefix for a particular collection within a library. These collections may be divided by former owners, as with several
British Library "closed" collections, or by language, as with
Froissart of Louis of Gruuthuse (BnF MS Fr. 2643-6), indicating a two volume manuscript in French at the . == See also ==