In Geoffrey Chaucer's Canterbury Tales, "The Summoner's Tale" follows "The Friar's Tale." The main character in "The Summoner's Tale" is an unnamed friar, who would go around to various people and preach in exchange for some gift of food, drink, or anything else he could get. In exchange for these gifts, the friar told his listeners that he would pray for them. The friar had some servants who would write down the listeners' names, but after he had left a house the names were immediately erased.
So, the friar is basically trying to bilk the people to whom he is supposed to be ministering out of anything he can get from them. In exchange, the friar will supposedly intercede with God on that person's behalf. The friar, however, finally gets his just reward when a certain Thomas, who has encountered several greedy friars already, gives the friar a gift he will never forget:
"Ah," thought the friar, "this shall go with me!"
And down he thrust his hand right to the cleft,
In hope that he should find there some good gift.
And when the sick man felt the friar here
Groping about his hole and all his rear,
Into his hand he let the friar a fart.