Count Vivian, the lay abbot of St. Martin at Tours, commissioned the lavishly illuminated Vivian Bible from the scriptorium at Tours, and presented it to Charles the Bald in 846 on Charles's visit to the church. It measures 495 mm by 345 mm, and has 423 folios.
Charles the Bald loved ostentation. "When, in the sixties and seventies, he had ostentatious manuscripts made in one of his residences (probably Soissons), achievements made in the Rheims and Tours schools were also absorbed into the new court style" (Bischoff, Latin Palaeography: Antiquity and Middle Ages  210).
The manuscript is preserved in the Bibliothèque nationale de France (BnF Lat. 1). A digital facsimile is available from BnF Gallica at this link.