 In March 1638 he was campaigning in the region of Delitzsch in the army of Johan Banér, getting complaints from the town for his alleged 'deprivations'.Within days units under Major General Adam von Pfuel pressed into Thuringia, with Douglas’s regiment among them.It was during this period that the Scot captured the Imperial Fälttygmästare (master of ordinance) Salis and his regiments, who were heading towards Eger (Cheb) in Bohemia.