This collection of Old English royal records is found in four manuscripts: London, British Library, Cotton Vespasian B. vi; London, British Library, Cotton Tiberius B. v, vol. 1; Cambridge, Corpus Christi College 183; and Rochester, Cathedral Library, A. 3. 5. The present paper aims both to provide an accurate, accessible edition of the texts in the first three of these manuscripts and to discuss the development of the collection from its origin to the stages represented by the extant versions. We owe to Kenneth Sisam most of our knowledge of the history of the Anglo-Saxon genealogies. Although his closely argued discussion remains the basis for any approach to these sources, it lacks the essential aid to comprehension, the texts themselves. It is perhaps this omission, as much as the difficulty of the subject and the undoubted accuracy of many of his conclusions, that has occasioned the neglect from which the texts have suffered in recent years.