Squadriglia 91a was one of the later fighter squadrons that the Italian Army created, on 1 May 1917. Because it drew an experienced cadre of pilots from pre-existing 70a Squadriglia, the squadron scored 14 victories within its first month of flying combat. As a result, it became known as "the squadron of aces". The new unit was immediately drawn into the ongoing Battles of the Isonzo in northern Italy.