A couple of weeks ago I mentioned Philippe-François de Merode (d.1742), 2nd Prince of Rubempré (shown above), and suggested that he acquired the illuminated Apocalypse that was later sold, in 1766, by his son, Maximilien-Leopold de Merode (1710-1769), 3rd Prince of Rubempré.
Of the other manuscripts in the 1766 Rubempré sale, at least one ought to be identifiable; lot 631 has a distinctive colophon at the end:
"Liber Decretorum ... anno Nativitatis J. C. 1326 Ego R. Joglar complevi seu perfeci Deo juvante Librum Decretorum ..."
"Liber Decretorum ... Anno Nativitatis J. C. 1326. Ego R. Ieglar complevi seu perfeci Deo juvante librum Decretorum ..."
This latter sale in 1734 is none other than that of Jean-Philippe-Eugène, count of Merode and marquis of Westerloo, which we also discussed two weeks ago.
In other words, even if we are ignorant of its present whereabouts, these two catalogue entries provide concrete evidence of a manuscript passing from the Merode-Westerloo collection, sold in 1734, to the Rubempré collection, sold in 1766, and therefore provides support for my (as yet unproven) suggestion that the illuminated Apocalypse manuscript sold in the 1766 sale is the same as the one sold in the 1734 sale.
Can we find more support of the same kind?
Lot 77 in the 1734 Merode-Westerloo sale:
"Histoire depuis le commencement du Monde jusqu'à Jesu[s]-Christ & l'Apocalypse de S[aint] Jean, en/sur velin, avec de très-belles & anciennes miniatures, preque à chaque feuille[t], & des ornemens d'or & de couleurs ..."
Surely they must describe the same manuscript, with the second description being based on the first.
Similarly, this was lot 17 in the 1734 Merode-Westerloo sale:
"Biblia Sacra sur velin très-propre, & d'un caractere fort ancien ..."
In isolation, a sceptic might suggest that when two descriptions such as these correspond, it is simply because cataloguers uses fairly formulaic language, and one medieval Bible often looks a lot like another one. But taken together with the other examples presented above (and doubtless I could find several more, if I checked more thoroughly), the obvious conclusion seems inescapable: the collection sold in 1766 had absorbed a number of items from the collection sold in 1734.
 I am grateful to Susan L'Engle, who also tried to track it down for me.