Last summer Maria Saffiotti Dale, Curator at the Chazen Museum of Art, sent me just the sort of provenance puzzle I enjoy. It concerned a 15th-century Italian cutting, shown above, described on the Chazen website as an "Initial 'D' from an Antiphonary from Como Cathedral with a Temple". 
On the back is an inscription which she could not entirely read: "I can make out all the inscriptions EXCEPT the initials(?) immediately preceding the date 1856 and what follows it. Any ideas?"
The Schoenberg Institute at the Kislak Center at the University of Pennsylvania is the only institution, as far as I'm aware, that regularly introduces its medieval manuscripts by way of YouTube videos; there are now more than 70 (including non-western MSS). I only recently became aware that one of these videos concerns not a codex, but two collages of cuttings, perhaps assembled in the 19th century, one of which is shown above.
This caught my attention because I had also recently been looking at other fragments from the same manuscript.