That branch of the Clan Alpine which is named the race of Dugald Ciar Mhor, was not commanded by Rob Roy at this momentous crisis, but by his young nephew, Gregor MacGregor, of Glengyle, who was lineal head of the house. Thus Rob served under him. Glengyle is best remembered in Scotland by his patronymic of Glun Dhu, or "Black-knee," from the remarkable spot, which his kilt rendered visible, on his left knee.
He was but a youth when the insurrection of 1715 took place, so there can be little doubt that, on most occasions, he would act under the eye and advice of a captain so skilful and bold as his uncle.
On the latter joining the insurgent camp in Braemar, he was at once despatched by the earl to Aberdeen, to raise in arms the descendants of 300 MacGregors, who had been forcibly conveyed there in 1624 by James Stewart, Earl of Murray, to fight in the feuds in which he became involved with the Grants, MacIntoshes, and others. In this mission Rob was pretty successful, for the popularity of his name, among his own clan and others made him an excellent recruiting officer at this crisis; and so little did he value the Whig Government and their proclamations that he walked openly about the streets of the Granite City, and on more than one occasion dined with Professor James Gregory, who was by descent a MacGregor, but had thus altered his name to elude the Act which proscribed it.
He joined the Earl of Mar in time to be present with his clan at the great battle of Sheriffmuir, where the insurgents met the king's forces led by the Duke o' Argyle, who was then lieutenant-general, knight of the garter, and commander-in-chief of the troops in Scotland.
It is no part of our plan to give any history of that indecisive battle, which was severe and bloody to both parties. Both armies wheeled upon their centres, and each routed the other's left wing, so that it is impossible to say with whom lay the victory.
On that day, Rob Roy, who commanded a body of MacGregors and MacPhersons, was accused of unwillingness to engage. His enemies went further, and asserted that, not wishing to offend his patrons the powerful Duke of Argyle and Earl of Breadalbane, save for whom he would have been crushed long ago by the Duke of Montrose, he remained almost aloof from the action. Lack of interest in King James's cause, or lack of courage could not be laid to his charge; yet on this great day the conduct of Rob Roy was incomprehensible.
Scott relates in his History, that when ordered to charge by one of Mar's aides-de-camp, he replied—
"If the earl cannot win the field without me now, he cannot win it with me."
From this it may be supposed that he considered the decisive moment past, and wished to spare his men; but, it is said, that on hearing this answer, a brave man of the Clan Vurich, named Alaster MacPherson, cast his plaid on the ground, drew his claymore, and called to the MacPhersons—
"Advance—advance!—follow me!"