Stitch in time
Vitae sanctorum. Source: gallica.bnf.fr Bibliothèque nationale de France, Département des manuscrits, Latin 17002, fol. 20v.
Early Book Repair
It looks like someone borrowed half a page long enough to sing a song or two, then stitched it back in. Breviarium …
Working around troubled parchment
Roman de la rose Source: gallica.bnf.fr Bibliothèque nationale de France, Département des manuscrits, Français 12593, fol. 154v.