The Italian military authorities decided in January 1941 to mount the excellent "Cannone da 90/53" on heavy or cross-country trucks to provide protection for the motorized columns against British armour threats.
At the same time, Ansaldo at Genova started to work on the project of the "Autocannone da 90/53" on Alfa Romeo chassis, but the military preferred the Lancia 3RO Autocannone instead.
The prototype of the "Autocannone Lancia" was completed on February 6, 1941 and its tests began on February 10.
One month later, on March 10, Regio Esercito placed an order for 30 specimens of Autocannone, changed to 10 specimens in April due to the upcoming Breda 51 truck, only to return finally to the 30 initial ones in September.
In total, Ansaldo delivered 30 Autocannoni on Lancia 3RO in 1941, used in Libya and Tunisia.
The IV^o Gruppo Autocannoni (on two batteries, for a total of 8 parts) was attached to the 133^o Reggimento Artiglieria of armoured division Littorio on October 25, 1941.
With the two batteries of 20 mm AA gun already on the spot, it constituted the IV^o Gruppo Misto.
Two other mixed groups with the equivalent composition were formed for the armoured divisions Centauro and Ariete.
In total, one thus counted 24 Autocannoni da 90/53 in North Africa, plus the 6 gun trucks of reserve.
The Centauro Gruppo took part only in the countryside of Tunisia.
In spite of the frightening effectiveness of the gun of 90/53 against the tanks, the Autocannoni Lancia were handicapped by their excessive height which made them easy preys in the Lybian desert plains.

Special Thanks to Mr. Lorenzo Tonioli, Italy for providing additional information