sentences:  Although Cranmer is concerned that "very simple and unlearned people" would understand and be edified by his book, the "Defence" is largely a polemic work, in which Cranmer attacked the Roman Catholic doctrine of his opponents, particularly Bishop Stephen Gardiner.In the preface he compares "beads, pardons, pilgrimages, and such other like popery" with weeds, but says the roots of the weeds are transubstantiation, the doctrine of the corporeal presence of Christ in the Eucharist, and the sacrificial nature of the Roman Catholic mass.The book itself is divided into five parts.