In Italy, the Allies suffered a long stalemate at the German Gustav Line. In May 1944, three Goumier groupes, under the name "Corps de Montagne", were the vanguard of the French Expeditionary Corps (CEF), under General Alphonse Juin, attack through the Aurunci Mountains during Operation Diadem, the fourth and final Battle of Monte Cassino. "Here the Goums more than proved their value as light, highly mobile mountain troops who could penetrate the most vertical terrain in fighting order and with a minimum of logistical requirements. Most military analysts consider the Goumiers' manoeuvre as the critical victory that finally opened the way to the Italian capital of Rome."