The P 26/40 was an Italian World War II heavy tank. It was armed with a 75 mm gun and an 8 mm Breda machine gun, plus another optional machine gun in an anti-aircraft mount. Design had started in 1940 but very few had been built by the time Italy signed the armistice with the Allies in September 1943 and the few produced afterwards were used by the Germans. The official Italian designation was carro armato ("armoured vehicle") P 26/40. The designation means: P for pesante ("heavy"), the weight of 26 tonnes, and the year of adoption (1940). History The development work began in 1940, on Benito Mussolini's specific orders. Initial requirements were for a 20 tonne (the maximum load allowed by pontoon bridges) tank with a 47 mm gun, three machine-guns and a crew of five, but this was quickly superseded by another 25 tonne design, to be named P26. The development work proceeded quickly except for the engine; the Italian military staff, the Stato Maggiore, wanted a diesel power-plant, while the builders favoured a petrol engine. However, in Italy at the time there were no engines (diesel or petrol) available capable of developing the required, and the Italian tank industry (i.e. the duopoly Fiat-Ansaldo) did not turn to easily available aircraft engines for its tanks as contemporary U.S. and British tank manufacturers had done. The design of a new engine was very slow, and in the end a petrol engine (Fiat 262) was eventually tested, even though in the end it was not adopted. Provisionally called P75 (from the gun's caliber), the first design (whose prototype was ready on mid-1941) was similar to an enlarged M13/40, but with a 75/18 howitzer (the same fitted on the Semovente da 75/18) and more armour; the prototype was then modified by replacing the main gun with a 75/32 gun with a co-axial machine-gun. After learning about Soviet T-34s in 1941, thanks to a captured tank supplied by the Germans, the whole design was radically modified: the armour was quickly thickened (from 40 to 50 mm on the front and from 30 to 40 mm on the sides) and re-designed, adopting more markedly sloped plates, and the new 75/34 gun was adopted; meanwhile the dual barbette mount in the hull was deleted. The gun designation "75/34" referred to a 75 mm bore diameter gun with a length equal to 34 calibres. However,