I enquired about this and other items, and was kindly sent images by Ronald D. Patkus, Head of Special Collections and Adjunct Associate Professor of History, and Dean Rogers, Special Collections Assistant. I was not at all prepared for what I received:
Having recently done a post on the Wildenstein collection in Paris, I realised that the two Vassar cuttings have a sibling there, with the same priest at the same altar in the same room with the same wall-hanging and same leaded window:
There are many cuttings and leaves from papal manuscripts scattered around the world, but most can be traced back to the famous auction of the Abate Celotti at Christie's, on 26 May 1825, always cited as the first ever auction dedicated solely to illuminated cuttings and leaves:
The Advertisement is signed by "W.Y.O.":
William Young Ottley (1771–1836), Keeper of the Department of Prints and Drawings at the British Museum.
Ottley bought a significant number of lots at the Celotti sale, and they were in turn included in his own posthumous sale fifteen years later, in 1838:
The present group of three cuttings can be identified as forming part of lot 219, or more probably 220:
"219 A sheet---Christ, with Emblems of the Passion, and seven small miniatures of Priests officiating at the Altar, enclosed in pieces of Border, with the Arms of Leo X.
220 Seven similar pieces of priests at the Altar"I will save for a separate post a discussion of the subsequent provenance of these cuttings; the parent volume; and its intact companion, which is now at the Morgan Library and Museum in New York.