war on 23 May 1915 the brigade participated in the conquest of Monfalcone on the Adriatic coast. Afterwards the brigade participated in the first four Battles of the Isonzo aimed at conquering the city of Gorizia. The brigade tried to capture the Sabotin hill near Gorizia and later fought at Oslavia. After the brigade had again fought at Oslavia in the Fifth Battle of the Isonzo it was transferred to the Asiago plateau to reinforce the Italian First Army, which was retreating under the massive Austrian-Hungarian Asiago offensive. There the brigade was sent to defended Monte Cengio - the last position between the Austrians and the Venetian plains. A loss of the mountain would have allowed the Austrians to advance towards Venice and encircle of Second Army, Third Army, and Fourth Army, which were holding the front along the Isonzo river and the Cadore and Carnia mountains. Arriving on Mount Cengio on 23 May 1916 the Granatieri held the position even after ammunition had been expended and the Austrians breached the brigade's line. Ultimately the stubborn defense of Mount Cengio ensured that the Austrians could not achieve the aims of their offensive. On 6 June 1916 the brigade was relieved on Mount Cengio, where it had suffered 4,478 casualties out of 6,000 men deployed. For their conduct both grenadier regiments were awarded a Gold Medal of Military Valour. After the Austrian offensive had been defeated the brigade returned to the Isonzo front and participated in the sixth, seventh, and eighth Battle of the Isonzo. During 1917 the brigade continued to fight along the Isonzo river. After the Italian defeat in the Battle of Caporetto and the following retreat to the Piave river the brigade had to be rebuilt. In 1918 the brigade fought in the last two battles on the Italian front: the Battle of the Piave River and the final and decisive Battle of Vittorio Veneto. After the war the brigade was garrisoned in Rome, where a third Grenadier Regiment was raised on 1 December 1926. On the same day the brigade with its three regiments came under the 21st Infantry Division. On that day the Grenadiers Brigade was renamed XXI Infantry Brigade, while its three grenadier regiments became the 1st Regiment "Granatieri di Sardegna", 2nd Regiment "Granatieri di Sardegna", and 3rd Regiment "Granatieri di Sardegna". World War II On 8 February 1934 the 21st Infantry Division was named