CCCC MS 321 is a fourteenth-century manuscript of Petrus Iohannis Olivi OFM (1247/8-96), Commentary on Matthew and Quaestiones. The texts of these have not been printed, save for extracts. The manuscript has been associated with the Benedictine abbey of Ramsey, but on evidence which Ker thought insufficient. It also contains an important eleventh-century fragment of an Old English dialogue about the word Alleluia, otherwise attested only in BL Harley 3271, and probably based on material from the pseudo-Bedan Collectanea. It is not clear whether Parker placed this fragment in the book, or whether it was already there when he acquired it.