|Fauvel holds forth.|
The story? It's about a horse ... a horse that becomes a politician.
The Roman de Fauvel ["Story of Fauvel"] is dated to as early as 1310, although the author is unknown. It is an allegory, in which a fawn-colored (French fauve) horse decides he is unhappy with the stable and moves himself into the largest room in the nearby house, altering it to suit his needs (like adding a crib for fresh hay). Fortuna (Fate) makes him the head of the house, and leaders both secular and religious come to listen to him, increasing his fame. Ultimately, Fauvel marries Lady Vainglory and begins a life of begetting corrupt leaders that will usher in the end times.
The original story was expanded by Chaillous de Pesstain*, who added musical notations to it—in fact, 169 snippets of musical notation to accompany the story. This particular copy is found in the Bibliotheque Nationale in France as manuscript BN fr. 146 (which you can see online here).
The Roman de Fauvel gave birth to a modern idiom. To "curry" is to groom a horse, and the leaders in the story would curry Fauvel in order to ingratiate themselves to him. "To curry Fauvel" became a saying to indicate trying to please someone so that they look kindly upon you. After the 17th century, this was misunderstood in English as "to curry favor," to try to get a favor from someone by flattery.
*And that's about the sum total of all we know about him. He may have been just the scribe of that particular manuscript.