Muriach Cattanach (Muireach Catanach), a 12th-century descendant of Gillicatton-moir, was "Prior or Parson of Kinguishie in Badenoch" when his elder brother, the chief of the Clanchattan, died childless. Muriach the Parson obtained papal permission to assume the chiefship and to marry, and was succeeded by his son Gillichattan Chlerich (the Clerk) and by his grandson Dougal Dall (the shortsighted) whose only daughter (or granddaughter) and heiress married Angus, 6th Chief of the Mackintoshes.
This latter event took place in 1291 AD and led to a controversy as to who was the legitimate leader of the Clan Chattan that has lasted, at different degrees of intensity, for over 700 years. The basis of the controversy was that the chiefship of Clan Chattan should have come to Ewan Bàn rather than the Mackintosh to whom that position was given. The circumstances surrounding this decision are not known but it is clear that it was the root of deep resentment on the part of the descendents of Ewan Bàn and probably a major factor that lead to the disintegration of the Old Clan Chattan.
Ewan Bàn had three sons -- Coinneach (Kenneth), Iain (John) and Gill-ìosa (Gillies). From these three brothers the entire Clann Mhuirich is said to be descended, and this lineage came to be known as the Sliochd nan Triuir Bhraithrean, the Posterity of the Three Brothers.
Highland historians have generally discounted the connections with the Chatti or with Caithness. Furthermore, Vatican records fail to reveal any papal dispensation or any association of 13th century Murdoch with the Priory of Kingussie which wasn't established until 1479. Although Sir Aeneas Macpherson's version has received wide acceptance from later clansmen in fact it owes practically nothing to the tradition of the clan except for some of the personal names, and should probably be held suspect as a version heavily contaminated with material drawn from Latin, Irish and French literary sources. On the other hand, the name Mac a' Phearsain was adopted by the members of all three sliochdan or lineages by the 16th century which would suggest that at least they believed that Muriach was the parson they grew from.