It was coming to live in Barnard Castle, within sight of the Balliol stronghold, which first aroused my interest in the world of the Anglo-Scottish ‘cross-border lords’ of the twelfth and thirteenth centuries, an interest which was further stimulated during post-graduate study at the University of Durham under the direction of Robin Frame. My first contact with the cross-border families was therefore made in the context of northern England rather than of Scotland. So when I was investigating the possibilities of further research and Keith Stringer suggested that the development of the early Brus family was a field as yet unexplored in depth, it was perhaps inevitable that I should envisage a study which would include both the main lines of descent, setting the Yorkshire line alongside their better-known kinsmen of Annandale. For although the name of Brus is now firmly associated with Scotland, it was in Yorkshire that the family was first established on this side of the Channel. It was the Yorkshire barony which was regarded as the primary inheritance and passed to the founder's eldest son. And while the Scottish branch of the family survived longer and ultimately rose higher, for much of the period of this study the Yorkshire Bruses were an influential force in their own region and played a formative role in the politics of northern England.