Before the Wars for Independence of the late 13th and early 14th centuries, those eastern districts had been the domain of the Comyns or Cummings family and their vassals. But the Comyns, one of the most powerful in all Scotland, opposed the efforts of Robert the Bruce to free Scotland from the occupation by the English forces of Edward the First and his son, Edward II. Bruce triumphed and the Comyns suffered the consequences.
Why the Clan Chattan families moved is not known for sure but tradition tells us that the move was authorised by the King of the Scots as a reward for their support of Bruce at Bannockburn in 1314 and elsewhere in the struggle that lasted until 1328. A glance at the map of Glen Loy and Loch Arkaig district displayed on Panel 006 shows that these lands are quite mountainous and thus unable to support the needs of all the growing population living there at the time. In any event, many of the Clan Chattan families invaded the lands of the Comyns followers and displaced them. Macpherson traditions tell of the many bloody battles and massacres that resulted. However, some of the families living there before the invasion were able to accommodate to living with their new neighbours. It is thought that the Clarks of Badenoch were one of these.
The migration was actually a rather leisurely affair, extending over three generations. It was the families of the two elder brothers, Kenneth and John, that participated in the first exodus and they must have borne the brunt of the fighting. The Gillies family remained at Letterfinlay in Lochaber until around 1450.