Sir Alexander Irvine, Fourth Laird of Drum, who was the great grandson of William de Irvine, was one of the chief commanders of the King's army at the battle of Harlaw, A.D. 1411. He was a valiant champion. Alexander lead the forces of Aberdeenshire with his cousin the Earl of Mar to meet the invaders from the Hebrides. Before the battle Alexander made his brother, Robert, swear that should he be killed, Robert would assume his baronial right at Drum. During the battle Alexander encountered the ferocious Chief of the MacLeans of Duart in Mull, known as Red Hector of the Battles. After 'noble and notable single combat' the two of them lay dead upon the field, killed by mortal blows struck upon each other. Many Irvines died in the battle of of Harlaw. Younger brother Robert carried out his oath and changed his name to Alexander and married his elder brother's fiancée, Elizabeth de Keith. Sometime later he led the delegation which negotiated the release of James I from the hands of the English, for which he was knighted.

The Battle of Harlaw - This battle, regarded by many today as the conflict between Highlanders and Lowlanders which killed the expansion of Gaelic influence, was one of the most brutal in Scottish history, becoming known as ‘Red Harlaw’.

While James I was growing up in English jails, Donald, Lord of the Isles made it his business to secure the Earldom of Ross’ estates before the Stewarts or Albany, the Governor of Scotland could, bringing his army westwards into Inverness and over the River Spey.
It may well have also been his desire to plunder and destroy Aberdeen.

His advance was met two miles past Inverurie at Harlaw. Coming from their north-eastern lands were a force of Keiths, Forbes', Leslies and Irvines, led by the Earl of Mar. They battled for most of 24 July until Donald’s men withdrew.
There were no winners or losers on the day but when James I returned to Scotland in April 1424 he quickly set about routing his foes.