ff. 8r-55r of MS 147 contain Peter of Ancarano's commentary on Book V of the Decretales Gregorii IX. Peter of Ancarano was a late-14th/early 15th-century canon lawyer who spent most of his career in Bologna. He followed in the line of several other 13th and 14th century jurists who produced commentaries on the Decretals of Pope Gregory IX. The Decretals of Gregory IX was produced in the first half of the 13th-century, and it formed the basis of medieval canon law. Peter of Ancarano is known as one of the principal commentators on this monunmental Church text.