The story of the deposition and death of Mac Con is told in The Battle of Mag Mucrama, §§59–77 of Stokes' edition, RC 13, 460–467, and there is an account of his death in the “historical” tract in Laud 610, edited by Meyer, Fianaigecht 28 (RIA Todd Lecture Series xvi, 1910). There is an independent story in YBL, which is here edited for the first time, and may represent one of the sources upon which the author of The Battle of Mag Mucrama has drawn. He did not merely copy it, for his text varies considerably in vocabulary, and by omission and addition. Yet the two texts are closely related, and Stokes' edition, referred to in the notes as L, has been of great value to me in reading and interpreting the text presented here. According to this text Mac Con was king of Ireland for thirty years, and this is also the tradition of the tract in Laud. In L he reigns for seven years (§59), but the alternative tradition is recorded in §77. In the LL text of the Battle of Crinna the period is twenty-seven years, LL fcs. 328 f 16 (O'Grady, Silva Gadelicaii, 491). The Annals of Tigernach say: Ailii aiunt Lugaid Mac Con post hoc bellum regnase [annis xviii] uel xxx ut alii aiunt, RC 17, 11. The source of the words in square brackets in Stokes' edition is not stated. It would be necessary to examine unpublished historical poems, genealogies, and regnal lists in order to trace the origin of these conflicting numbers. Confusion often arises from the use of Roman numerals in manuscripts.