Promoted Field Marshal in 1792, he was appointed to raise and command the 3,873 man Hanoverian electoral contingent to the Holy Roman Empire.
Freytag commanded the Hanoverian troops and the 13–15,000 man Austro-Hanoverian corps under the Duke of York in the Flanders Campaign in 1793, seeing action at Rüme (St.Amand) 1 May, Famars 23rd, the siege of Valenciennes 13 June-28 July, and Cæsar's Camp 7/8 August.
On 6 September he was driven back by Houchard at the Battle of Hondschoote, where he was wounded and captured, but rescued the following day by Wallmoden’s counter-attack.
At St. Amand 1 May York tried to locate him & Bussche to bring their troops forward, "but found neither at home, because they too had ridden out to reconnoitre, which annoyed the Duke very much, because he had expected to find them in their quarters.
In my opinion Freytag occupied the best possible position; his mistake was that he was forgetful of the principal of maintenance of the objective – namely, to cover the besieging army – till pulled up sharply and rightly by the Duke...