During the North African campaign, the Italian military quickly realized the effectiveness of their 90mm heavy AA cannon, commonly mounted on utility trucks. The cannon turned out to be just as good at dealing with enemy tanks as it was combating aircraft, being able to pierce the armor of virtually any allied tank it faced in the deserts of North Africa. However, whilst the mounting on truck chassis allowed the guns to be moved around with relative ease, the large silhouette and lack of armor protection heavily exposed these vehicles and their crews to even rifle-caliber fire, yet alone to shrapnel from nearby explosions. In 1942, the military top brass came up with a set of requirements for a new vehicle which would build up on the proven gun truck concept used in North Africa by increasing protection and mobility. The new vehicle would be designed as a dedicated SPG, intended solely to provide support to armored regiments in combating enemy tanks. Shortly after, the Breda company began work on a vehicle around those specifications. Breda based their new design on a chassis of an existing utility truck and added armor plating to the vehicle’s front and sides. The 90mm cannon would be installed in an open fighting compartment in the vehicle’s rear. In 1943, the prototype was finished and began undergoing testing as the Breda 501. Although the Breda 501 had successfully proven itself during testing, further development and potential mass production was hindered by Italy’s capitulation in late 1943. The project was ultimately cancelled with the signing of the armistice in late 1943 with only a couple prototypes of the Breda 501 being built of which none saw any combat use.