He had wanted, above all things, to finish with the Austrians; so as to be able to move off to the other points threatened.
He now arranged that Bevern and Winterfeld should take the command in his absence, watch the Austrians, and guard Silesia; while he, with 23,000 men, marched on the 31st of August from Dresden, with the intention of attacking the combined French and German Confederacy force, under Soubise, that had already reached Erfurt.
Keith accompanied the king on his harassing march.
Since the arrival of the army at Leitmeritz, Fergus had been incessantly engaged in carrying despatches between that town and Dresden; and worked even harder while the king was trying, but in vain, to bring about an engagement with the Austrians.

For the first few days after starting for Erfurt, he had a comparatively quiet time of it.

The marshal was now constantly the king's companion, his cheerful and buoyant temper being invaluable to Frederick, in this time of terrible anxiety.

Fergus would have found it dull work, had it not been for the companionship of Lindsay, who was always light hearted, and ready to make the best of everything.
"I would rather be an aide-de-camp than a general, at present, Drummond," he said one day.

"Thank goodness, we get our orders and have to carry them out, and leave all the thinking to be done by others! Never was there such a mess as this.