Ysengrimus is a Latin fabliau and mock epic, an anthropomorphic series of fables written in 1148 or 1149, possibly by the poet Nivardus. Its chief character is Isengrim, the Wolf; the plot describes how the trickster figure Reynard, the Fox, overcomes Isengrim's various schemes. The author Little is known about Nivardus. All that can be said of him with any certainty is that he lived in the 12th century, and was closely connected to Ghent. The text is anonymous in the manuscripts containing the whole poem. Florilegia and medieval catalogues give the author's name variously as "Magister Nivardus", "Balduinus Cecus" (Baldwin the Blind), and "Bernard". The poem The Ysengrimus draws on earlier traditions of beast fable in Latin, such as the 11th-century Ecbasis captivi; in the Ecbasis, the now traditional opposition of wolf and fox appears. The Ysengrimus is the most extensive anthropomorphic beast fable extant in Latin, and it marks the first appearance in Latin literature of the traditional names "Reinardus" and "Ysengrimus". The poem runs to 6,574 lines of elegiac couplets. The Ysengrimus is divided into seven books, which contain twelve or fourteen tales; opinions differ on how to divide them. Other beast fables were written by other medieval Latin authors, including Odo of Cheriton; the Ysengrimus is the most extensive collection of this material either in Latin or in any vernacular. The poem mixes medieval and classical Latin imitations and parts of it are written in a curious, difficult style featuring obscure verb forms such as deponent imperatives. These stylistic curiosities reflect neither deliberate obscurantism nor lack of poetic talent; they are, instead, means of characterization. The poet places them on the lips of the trickster Reinardus, who is intended to be deceptive, and whose statements contain deliberate ambiguity. Ysengrimus is made to speak in a similar style when he is lying. But when he has been deceived into a predicament, he speaks plainly. In the opening episode of Ysengrimus, the wolf manages to successfully deceive the fox by one of his schemes; this is Ysengrimus's only triumph, and throughout the remaining episodes Ysengrimus is constantly being tricked or humiliated by Reinardus. The poem contains the well known story in which Reinardus deceives Ysengrimus to go ice fishing using his tail as a net, only to get it frozen into the lake. When Reinardus mockingly urges Ysengrimus to get up quickly, Ysengrimus is made to say: Captus