The Chaucer Review: An Indexed Bibliography (Vols. 1-30)

Haskell, Ann S. "The St. Giles Oath in the Canon's Yeoman's Tale." 7 (1973): 221-26.
The oath which the Canon's Yeoman swears by St. Giles supports the idea that alchemists are social outcasts. By its placement in the description of an alchemical process, it also draws attention to the sinful nature of the coupling of elements with which the Canon intends to trick the priest. The oath emphasizes the spiritual side of alchemy, since the alchemist's purity had direct effects on the metal he wished to purify. St. Giles was the patron saint of lepers and lechers and was associated with fennel, an aphrodisiac and cure for eye disease. St. Giles was also reported to have achieved pardon for a sin so terrible it could not be confessed. The St. Giles oath points to charity and chastity.