The famous Celotti auction at Christie's in 1825 consisted largely of very late 15th-century and 16th-century papal illuminations from the sacristy of the Sistine Chapel. The sale has received a lot of attention in recent decades, reaching a cresecendo about a decade ago: in the late 2000s Anne-Marie Eze catalogued the cuttings now at the British Library (and traced sister-cuttings in other collections) and submitted her PhD thesis on Celotti in 2010; in the same year Elena De Laurentiis covered some of the same ground in the exhibition The Lost Manuscripts from the Sistine Chapel. Each of them, and others, have also published articles on various aspects of the Sistine manuscripts and their fates. 
It is partly because the Celotti cuttings have already been so well studied that my own focus has been the other great 19th-century sale of illuminated cuttings, that of W.Y. Ottley, in 1838, as regular readers will be well aware. I do, however, think I have one small contribution to make concerning Celotti.