Among the glossators of Gratian’s *Decretum* there is a Willelmus who is held by some to be our W. N., while others attribute the glosses to Guilelmus Guascus.
About the year 1234 he wrote a *Commentary* or *Lecture* on the Decretals of Gregory IX, analyzing the individual chapters with a methodical approach. The work remains unpublished: fragments have been edited by Trifone, who has also reviewed all the Cassinese manuscripts containing works by W. N. (*Gli scritti di G. N. conservati nella Biblioteca di Montecassino*, in *Rivista di storia del dir. ital.*, 2 [1929], pp. 242–60). Among his works are glosses on the *Compilationes antiquae*, allegationes and repertationes on the Decretals of Gregory IX, a *Summa* on the same, and distinctiones and repetitiones on the *Decretum* and on the Decretals.