For the last week or so, I’ve been lost in another world – in the sea-spray glinting off a longship’s figurehead, and the sheen of sunlight on helms and spears. It is the dawn of the 11th century. Viking culture, with its pillaging, sagas and piratical leaders teeters on the edge: and, falling, begins to assume the Christian values and the lineaments of the world we know today. It is also the moment when one man, by chance or the will of the Fates, finds himself in a position to begin unifying the disparate earldoms of Alba, Caithness and Orkney into a political entity that will assume the more familiar name of Scotia. That man is here most often given his pagan, Norse name: Thorfinn. History knows him by a much more famous name. Macbeth.