The article is devoted to the study of two iconographic arrangements that accompany the prose rewritings of the legend of the purgatory of St Patrick in two manuscripts in the Arras Municipal Library (302 and 657). It should be recalled that there is very little iconography linked to this legend, which nevertheless has some characteristics that would seem to favor representation : an emphasis on a terrestrial entryway, geographically located in the afterlife, numerous descriptions of locations, a highly individualized hero, etc. Nevertheless, the difficulty in creating an image seems above all to lie in the representation of the transitory nature of purgatory in relation to hell. The study demonstrates that painters represented punishments rather than a particular place and took from the texts an interpellating dimension, following the demonstrative and persuasive reasoning of texts.