Beginning with a consideration of Malory's ingenious chronology, this study shows that Malory achieved thematic and structural unity by selecting from the great mass of Arthurian legend three narrative strands—the intrigues of Lancelot and Guinevere, the Grail quest, and the feud between the houses of Lot and Pellinore—using these to illustrate a single theme—the rise, flowering, and downfall of an ideal civilization. This selection and use of diverse materials, Charles Moorman asserts, indicates clearly that Malory set to work with a preconceived plan and that he did achieve his purpose, to write the "haole book of Kyng Arthur."