In 1799 the 49th was assigned to the Helder Expedition against the Batavian Republic (now known as the Netherlands), to be led by Sir Ralph Abercromby. During the troop landings, Brock saw his first combat on 10 September 1799 under the command of then-Major-General John Moore. Given that the 49th was in poor shape when Brock took command, they saw little actual combat. Likely Moore was sparing them and using more experienced troops to establish the beachhead. Finally on 2 October the 49th was actively involved in heavy combat at the Battle of Alkmaar, where they acquitted themselves well, sustaining only 33 deaths.