This posting deals with a peculiar variation on the ‘knight v. snail’ theme in a manuscript kept in the Bibliothèque Municipale, Angers. It is entitled “Compost et calendrier des bergiers”, and is dating from 1493 .
The use of calendars starts in the 12th century in the books used by clerics such as psalters , missals or martyrologies. At the end of the Middle Ages, Books of Hours always start with a schedule that shows the religious festivals.
Calendars and ‘compost des bergers’ are different in nature. Meant to “teach science of shepherds is science of the soul, body, stars, life and death,” these books are actually compilations for moral and practical use for the lay public. They are inspired by medieval works such as “The Book of properties of things ” of Bartholomew the Englishman, and the “Big Dance Macabre” preparing souls at the Last Judgement. They use astrology (very prominent in the 15th and 16th centuries), Zodiac signs , anatomical plates, the dance of death or representations of hell, representations of agricultural or craft activities for each month of the year, and should enrich the text to guide man to salvation. The first ‘compost des bergers’ was printed in Paris by Guy Marchant in 1491 before being reissued many times in the following decades. 
On folio 89r a miniature is shown with two knights (one with sword and shield, the other with a lance), and a woman holding a spade with her two hands above her head. They are all ready to attack a relatively large snail on a tree trunk. In the background a castle is visible.
The snail is stylised and humanised, with two tentacles and an eye; it looks like a rabbit or hare. The shell is sinistral, has only a few whorls and a corrugated apertural lip.
This picture is special, because this one of the few with multiple persons opposing the snail . It reminds a picture in this manuscript, except that there is now more than one person.
The ‘debate of men-at-arms and a woman against a snail’ has been discussed by Pinon , who refers to and older version of the manuscript with an illustration by Antoine Vérard (“the Woman with a Bold Courage (…) is first to address the snail, standing threatingly, horns extended, at the top of a watch-tower on a fortified castle”). This was figured in his plate 8:
Pinon also gives examples from later copies of this figure, e.g. his plate 7 (from an undocumented source), and plate 6 (from Novati 1905).
But the most interesting source is his plate 5, which is a 14th century object in the British Museum. As I have been unable so far to trace this I here copy Pinon’s figure.
As he argued, the snail as watchman on a watch-tower could have been intended as merely pun and “really quite amusing”. 
 Angers, BM Ms. impr. Rés. SA 3390, 95 ff. http://bit.ly/1jlwrSJ.
 Modified after http://bit.ly/1kmdqU0.
 According to Sarah Biggs (British Library) this is one of the few examples she knows (pers. commun. 9.i.2014).
 Pinon 1980, p. 81.
 Pinon 1980, p. 109, note 43.