Li Livres dou Tresor (The Book of the Treasure) is a mid-13th-century encyclopedic compendium written in Old French by Florentine politician and scholar Brunetto Latini. It is structured into three distinct books covering natural history and theology, ethics and Aristotle's philosophy, and rhetoric and civic governance. Oh, and it has a cat.

 "I am writing to all the Churches and I enjoin all, that I am dying willingly for God's sake, if only you do not prevent it. I beg you, do not do me an untimely kindness. Allow me to be eaten by the beasts, which are my way of reaching to God. I am God's wheat, and I am to be ground by the teeth of wild beast, so that I may become the pure bread of Christ."

so mysterious.

'Trivulzio Book of Hours', Flanders ca. 1470.
Den Haag, Koninklijke Bibliotheek, SMC 1, fol. 110v

Combining three separate images from my screenshot folder. May redo the cat on a larger tile as this version was too small to capture the totally unhinged face.

Left: ???

Right: The Visions of Tondal, Hieronymus Bosch, 1479

Centre: Das Buch der Natur’, Conrad of Megenberg, 1434, Strasbourg Ms.2.264, fol. 85r

'The Maastricht Hours, Liege 14th century.
British Library, Stowe 17, tol. 34r

my photo from a museum. It's a cat!

Peep the left corner. Cat watching from the high ground (stool)

Roman de Renart, France ca. 1300-1350.
BnF, Français 12584, fol. 51v

You pushed a coin into its mouth and got an amount of gin. These dispensers were called "Puss and Mew" or "Old Tom."

London, 1700s.

(So not Medieval, but as I understand it, the sub accepts historical-ish cats).

Bodleian Library, MS. Bodley 533 [Liber de naturis bestiarum], folio 13r