It was not composed by a single individual, but is presumed to have been compiled and performed as a unit.
It is not completely clear whether the Mass portions included in the manuscript were intended as a complete polyphonic setting of the Mass, or merely represent isolated movements.
They were inscribed in empty spaces in a manuscript that otherwise contains plainchants and texts.
The manuscript is also missing a polyphonic Gloria in excelsis Deo and Credo.
However, it does include a note identifying a motet on Ite, missa est following the Sanctus and Agnus Dei (which appear adjacently in the manuscript).