The Earl had doubtless been won over by Mar to resign his English commission, and desert King George for King James. The story is told that, as he rode North from London in 1715 to join Mar in the Highlands, he met his young brother James riding South to take service with King George. He easily induced his brother to share his own fortunes, and Prussia ultimately gained the great soldier thus lost to England. The Covenanting historian, Wodrow, avers that ‘Marischal was bankrupt,’ and therefore eager for _res novæ_. But he would have been a Jacobite in any case. As to the Earl’s conduct when Mar’s ill-organised and ill-supplied rising drew fatally to a head at Sheriffmuir, his brother, the Field-Marshal of Prussia, in his fragmentary Memoir, tells all that we know. The Earl, with ‘his own squadron of horse’ and some Macdonalds, was sent to occupy a rising ground, the enemy being, as was thought, in Dunblane. From the height, however, the whole hostile army was seen advancing, and the Earl sent to bid Mar bring up his forces. There was much confusion, and the Earl’s squadron of horse was left in the centre of the line. Mar’s right with the Earl routed Argyll’s left, while Argyll’s left routed Mar’s right. ‘In the affair neither side gained much honour,’ says Keith, ‘but it was the entire ruin of our party.’ Half of Mar’s force, having thrown down their plaids,[3] were now unclothed: many had deserted; the evil news of the Preston surrender came, the leaders were at odds among themselves, 6,000 Dutch troops were advancing from England. Seaforth and Huntly took their followers back to the North, and when King James arrived at Perth, late in December, he found a wintry welcome, soldiers few and dispirited, and dissensions among the officers. The army wasted away while Cadogan, Argyll, and the Dutch troops, greatly outnumbering the Jacobites, advanced on Perth through the snow.