Among men of the Middle Ages no theme, religious or secular, was more widely popular than the motif of the Seven Deadly Sins. From summae and sermons, from “mirrors” and manuals, from hymns, “moralities,” and books of exempla, from rules of muns and instructions of parish priests, form catechisms of lay folk and popular penitentials, and finally from such famous allegories as De Guileville's Pèlerinage every medieval reader gleaned as intimate a knowledge of the Sins as of his Paternoster and his Creed, and hence was able to respond to every reference to these, explicit or implicit. Moreover this theme, which had absorbed the attention of Dante through many cantos of his Purgatorio, so familiar to Chaucer, had, in our poet's own day, won vivid portrayal from Langland in Piers Plowman and had claimed eighteen thousand lines of prolix analysis in the Mirour de l'Omme of the moral Gower. And even now, while Chaucer's own Tales were in the making, Gower's Confessio was reared high upon the foundation of general interest in this motif. No wonder that it made an irresistible appeal to Chaucer too!