|"Ego Ioh(ann)es sc(ri)psi hunc librum"|
Baltimore, WAM, MS W.761 fol. 1r [Source]
The volumes have had a succession of illustrious modern owners, including John Ruskin, Henry Yates Thompson, Alfred Chester Beatty, and William Randolph Hearst; it is now at the Walters Art Gallery, Baltimore (MSS W.759-762), where it has been fully catalogued and digitized.
When John Ruskin owned it, he extracted a number of leaves to give to friends. A few of them contained major decoration, but most were much more ordinary-looking text leaves, and these occasionally appear on the market.
This leaf, for example, turned up in an antique shop on the Isle of Wight (it is presumably no mere coincidence that the Isle of Wight is home to Bembridge School [Wikipedia], which owned a major collection of art, manuscripts, printed books, and other memorabilia relating to John Ruskin); it was sold at Sotheby's in 1988 to a Belgian private collector, who resold it in 2015:
In addition to the 17th/18th-century  pagination in arabic numerals in the top outer corners, which run throughout the volumes, leaves were also foliated in late-medieval roman numerals in the fore-edge margin of rectos, with the numbering re-starting at the beginning of the Common in each volume. Last year I was able to take photos that clearly illustrate these paginations and foliations on the Lilly Library's seven Beaupré Antiphonary leaves:
|[Click to enlarge]|
Two leaves that seem to have eluded recognition are among a miscellaneous group which comprise MS Add. 6219:
The existence of the other leaf was not previously postulated, because the highest page number previously known was "602" (the ex-Sotheby's leaf shown above), and it was uncertain what, if anything, followed it.
The provenance of the Beaupré volumes has been described in detail in print a number of times (and is summarized online here). These particular leaves belonged to Alexander Gordon Wynch Murray, Librarian of Trinity College, Cambridge, who died aged only 34 in 1919.
 C. de Hamel, Gilding the Lilly (Bloomington, 2010), no.35.
 L. Randall, "The Fragmentation of a Double Antiphonal from Beaupré", in Interpreting and Collecting Fragments of Medieval Books (Los Altos Hills and London, 2000), pp. 210-29 at p.216 n.17, reports Michelle Brown's opinion that the pagination is pre-1700; de Hamel (as above) suggests (more plausibly, in my opinion) that the pagination was added during the time of Abbess Angéline de Lossy, 1755-96.
 P. Binski, P. Zutshi, and S. Panayotova, Western Illuminated Manuscripts: A Catalogue of the Collection in Cambridge University Library (Cambridge, 2011).
 S. Panayotova, et al., A Catalogue of Western Book Illumination in the Fitzwilliam Museum and the Cambridge Colleges (London and Turnhout, 2009- ).
 L. Randall, Medieval and Renaissance Manuscripts in the Walters Art Gallery, Vol. 3: Belgium, 1250-1530 (Baltimore, 1997), no.219.