In a letter from Leslie, dated the twentieth of January, 1716, it is stated that the country did not oppose the incursions of Rob Roy, being mostly in his interest, or indifferent. Emboldened by this passive conduct, Rob Roy marched to Falkland on the fourth of January, 1716, and took possession of the palace for a garrison. He afterwards joined the Earl of Mar's forces at Perth, yet, whether from indolence or caution, took but little share in the signal events of the day. He hovered sometimes in the Lowlands, uncertain whether to proclaim peace, or to embark with his Macgregors in the war: some said he declined fighting under Lord Mar, from the fear of offending the Duke of Argyle; at all events he had the wiliness to make the belligerent powers each conceive him as of their respective parties.
At the battle of Sherriff Muir, Macgregor had the address to make both the Jacobites and Hanoverians conceive, that, had he joined them, the glory of the day would have been secured.
The inhabitants of Leslie, who had heard, with dismay, the news of the burning of Auchterarder and Blackford, were now affrighted by a rumour that Rob Roy had a commission to burn Leslie, and all between that place and Perth. But, whilst the burgesses of Leslie were daily looking for this dreaded event, Rob Roy was forced to retreat to Dundee, by the approach of the King's troops. He left behind him a character of reckless rapacity, and of a determined will, notwithstanding some generous and humane actions. He was, nevertheless, esteemed to be among the fairest and discreetest of the party to whom he was attached, notwithstanding his favourite speech, "that he desired no better breakfast than to see a Whig's house burning." The people could not, indeed, trust any man's assurances after the recent and cruel devastation at Auchterarder.
When the fortune of the battle was decided, he was heard to say, in answer to demands that he should send his forces to the attack, "If they cannot do it without me, they cannot do it with me," and he immediately left the field. Such is the popular account of his conduct on that occasion.
The partizans of Rob Roy have, however, given a very different version of his conduct. The Duke of Argyle was the patron and friend of Macgregor; and he could neither, therefore, openly adopt a course which the Duke disapproved, nor would he altogether retire from a cause to which he was disposed to be favourable. With the true Gaelic caution Rob Roy waited to see which side prevailed, and then hastened to avail himself of an opportunity of that which had become the darling pursuit of his existence—plunder.
He retired from Sherriff Muir to Falkland, carrying terror wherever he passed.
The following letter, descriptive of his progress affords a curious picture of the state of that harassed and wretched country:—
"D. B.