The Brialmont forts would be used for the first time after Brialmont's death during the German invasion of Belgium in 1914. The system of fortifications established by Brialmont was at the heart of the ultimately unsuccessful Belgian defensive strategy and led to decisive battles at major fortified regions, including the Battles of Liège, Namur and Antwerp between August and October 1914. Ultimately the fortifications proved ineffective against new, large caliber German siege artillery such as the "Big Bertha" and Austrian Model 1911 howitzers.