After the defeat at Caporetto the Italian army was forced to retreat from the Isonzo river to the Piave river. During the retreat four Bersaglieri regiments and three autonomous battalions were so badly mauled that they had to be disbanded: besides the wartime regiments 15 and 21, also the peacetime regiments 4 and 9 were disbanded. Thus at the end of 1917 the Bersaglieri corps consisted of: