A pibroch, from the Gaelic ‘piobaireachd’, is a piece of music which can only be played on the Great Highland bagpipes, consisting of a theme and a series of variations. Like its companion The Ballad, The Pibroch does not represent a specific moment in Scottish history but symbolises war as Highlanders charge down a hillside, weapons at the ready. This echoes the personifications of peace and war in the spandrels on the top left and right of the Portrait Gallery’s main entrance: the two states in which people live at any given time and ‘the occupations of those who are found worthy of a place in the building’.