The bombardment was followed by a poison gas drop. Once the gas had lifted, the main infantry assault by 17 German "Sturmtruppen" divisions commenced, part of an Army Group nominally commanded by Crown Prince Wilhelm, the eldest son of Kaiser Wilhelm II. The Kaiser came to inspect the progress of the battle. He interviewed captured British Brigadier-General Hubert Rees (GOC 150th Brigade, part of 50th Division). The Kaiser was amused to learn that he was Welsh, the same nationality as Lloyd George.