So far: Leaves in the Canon section have only fifteen lines per page instead of twenty-one. Many Canon leaves preserve marginal instructions to the priest, telling the celebrant how to handle the host, what to do with the chalice, when to kneel, and so on: “Uncover the chalice and take up the Host.” The three extant historiated initials are found in this section, in the Preface of the Mass.
Lingering questions: The text holds at least one surprise. The prayer Aufer a nobis, in the right-hand column of the recto of the leaf at Oberlin (shown here), is in an atypical position, immediately following the Sanctus. In the standard Roman Mass, this prayer occurs quite a bit earlier, practically at the beginning. Te igitur should come right after the Sanctus; the insertion of Aufer a nobis could have been an attempt to correct an earlier omission, or it could be a local variant. Something unusual is going on. This is one of the only extant leaves with line-fillers, and the verso is blank, suggesting that the scribe was trying to wrap up this leaf before beginning something pretty special on the still-missing facing page. The 1926 Sotheby's description counts four historiated initials, all in the Canon. The fourth may have been on the lost next page, perhaps a large historiated [T] for Te igitur.