While the Earl of Cromartie and other clan historians accept the Fitzgerald origin by marriage with a daughter of Kenneth Matheson of Lochalsh, the Mathesons maintain that the first Mackenzie, or Mac Choinnich - the actual progenitor of the clan - was a son of their chief, Coinneach Gruamach, and that the Mackenzies are thus only a sept, or minor branch of the Mathesons. It must in fairness be admitted that the latter contention is quite as near the truth as the Fitzgerald theory and it must have already occurred to the reader, how, if the Fitzgerald origin of the Mackenzies had been true, has it come about that the original patronymic of Fitzgerald has given way to that of Mackenzie? It is not pretended that it was ever heard of after Colin himself. This difficulty occurred even to the Earl of Cromartie, and this is how he attempts to dispose of it. Cailean, he says, had a son by the daughter of Kenneth Mac Mhathoin, or Matheson, whom he named Coinneach, or Kenneth, after his father-in-law Kenneth Matheson; Cailean himself was killed in Glaic Chailein by Mac Mhathoin, who envied him, and was sore displeased at Colin's succession to Matheson's ancient heritage; Colin was succeeded by his son Kenneth, and all his descendants were by the Highlanders called "Mac Choinnich," or Kenneth's son, taking the patronymic from Mac Mhathoin rather than from Cailean, whom they esteemed a stranger. Of the two theories the Matheson one is by far the more probable; but they are both without any real foundation. The Fitzgerald theory has, however, until recently, been accepted by all the leading Mackenzie families and by the clan generally. It has been adopted in all the Peerages and Baronetages, and by almost every writer on the history and genealogy of the Cabar feidh race. The main if not the only authority of any consequence in favour of this Irish origin is the charter alleged to have been granted by Alexander III. to Colin in 1266, of which the reputed original runs as follows:- "Alexander, Dei Gracia, Rex Scottorum, omnibus probis hominibus tocius terre sue clericis et laicis, salutem sciant presentes et futuri me pro fideli seruicio michi navato per Colinum Hybernum tam in bello quam in pace ideo dedisse, et hac presenti carta mea concessisse dicto Colino, et ejus successoribus totas terras de Kintail. Tenendas de nobis et successoribus nostris in liberam baronium cum guardia. Reddendo servicium forinsecum et fidelitatem. Testibus Andrea episcopo, Moraviensi. Waltero Stewart. Henrico de Balioth Camerario. Arnoldo de Campania. Thoma Hostiario, vice-comite de Innerness. Apud Kincardine, IX die Jan.: Anno Regni Domini, Regis XVI."