The Brus, also known as The Bruce, is a long narrative poem, in Early Scots, of just under 14,000 octosyllabic lines composed by John Barbour which gives a historic and chivalric account of the actions of Robert the Bruce and the Black Douglas in the Scottish Wars of Independence during a period from the circumstances leading up the English invasion of 1296 through to Scotland's restored position in the years between the Truce of 1328 and the death of Thomas Randolph, Earl of Moray in 1332.
The poem's centre-piece (literally) is an extensive account of the Battle of Bannockburn of 1314. Barbour's poetic account of these events is a keystone in Scotland's national story. The description of the battle is Barbour’s masterpiece.
The poem was written about 1375, "...to throw behind the new king, Robert II (who gave Barbour a pension) the weight of his grandfather's (Bruce's) achievements and reputation." Barbour's work is a romance based upon a lost life of Douglas and a chronicle or chronicles which told of King Robert and his times. At the beginning of the poem, he conflates three Bruces into the single person of the hero, probably by design. Archie Duncan notes Barbour's fondness for exaggerated numbers for the size of any army. Here and there the order of events is transposed. Despite this, it has been regarded from his own time as, in all details, a trustworthy source for the history of the period.
Throughout the piece, Bruce overshadows all his associates. In book nine, in recounting Edward Bruce's victories in Galloway, Barbour does not relate the whole story, but sums up his worthiness by remarking that "he might have rivaled any of his contemporaries excepting only his brother". The king is a hero of the chivalric type common in contemporary romance; freedom is a "noble thing" to be sought and won at all costs; the opponents of such freedom are shown in the dark colours which history and poetic propriety require; but there is none of the complacency of the merely provincial habit of mind. The lines do not lack vigour; and there are passages of high merit, notably the oft-quoted section beginning "A! fredome is a noble thing".