I really share Alan Reilly's point of view. Excellent.
The Scots (originally Irish, but by now Scotch) were at this time inhabiting Ireland, having driven the Irish (Picts) out of Scotland; while the Picts (originally Scots) were now Irish (living in brackets) and vice versa. It is essential to keep these distinctions clearly in mind (and verce visa). Sellar and Yeatman