More generally, the series draws from many mythological sources as inspirations, especially Celtic (see Tír na nÓg), Norse mythology, and Arthurian legend. Zelazny cited Jessie L. Weston's 1921 book "From Ritual to Romance" as a key influence: it examined the pagan and Christian roots of the legends of King Arthur, the Wasteland myths, and the Holy Grail. For example, the Celtic Wasteland myth ties the barrenness of a land to a curse that a hero must lift; Corwin's curse is in part responsible for the Black Road.