On September 4th Montrose left Perth for Aberdeen. In point of equipment his force was now vastly superior to that he had led to victory at Tippermuir. His men were all well armed and clothed; ammunition was plentiful, and there was some money in the chest. A few gentlemen joined him on the march. Among them was the gallant old Earl of Airlie, with his two younger sons Sir Thomas and Sir David Ogilvy, who through good and evil fortune remained faithful to the end; and Nathaniel Gordon, one of the bravest and the most constant of his name. These brought a welcome addition to his force in the shape of a small body of cavalry, not indeed exceeding fifty troopers, but all well mounted and well armed. On the other hand there had been some serious defections. As usual, most of the Highlanders had gone off to the mountains to secure their booty. Lord Kilpont's men had withdrawn with the body of their young chief, after his mysterious death at the hands of his kinsman Stewart of Ardvoirlich, which had occurred in camp on the morning after they had left Perth.[16] When Montrose summoned Aberdeen on the morning of September 12th, he had at his back only fifteen hundred foot, fifty horse, and the few field-pieces taken at Tippermuir. The Covenanters were two thousand strong in foot, with five hundred horse. Two of Huntly's sons were among them. It is idle to search for the causes which placed these scions of a loyal House in the ranks of their sovereign's enemies. One cause was undoubtedly jealousy of Montrose, whose treatment of their father they had not yet forgiven. Moreover, though Huntly's sons, they were also Argyll's nephews, and for the present the uncle had the upper hand of the father. There at all events they were, not only marshalled to fight against the King's troops, but marshalled side by side with their hereditary foes, the Crichtons, Frasers, and other families who welcomed the Covenant as a counterpoise to the overweening power of the Gordons. But though superior in numbers, and not inferior in arms and courage, the Covenanters were totally deficient in discipline, and their nominal leader, Lord Balfour of Burleigh, had neither knowledge nor authority to control them.