The Christ Church manuscript is a 15th century copy of the Hebrew
translation prepared by Moses ibn Tibbon in 1271 of Muhammad ibn
Ayyash al-Hassar's seminal 12th century Arabic treatise on
arithmetic, Kitāb al Bayān wa-l-tadhkār.
For a detailed description, please see
www.chch.ox.ac.uk/library-and-archives/digital-library.