their disadvantage in protection and firepower. At one point, von Thoma offered up to 500 pesetas for each T-26 captured. Although the Panzer I was initially able to knock out the T-26 at close range—150 meters (165 yd) or less—using an armor-piercing 7.92 millimeter bullet, the Republican tanks began to engage at ranges where they were immune to the machine guns of the Panzer I. The Panzer I was upgraded in order to increase its lethality. On 8 August 1937 Major General García Pallasar received a note from Generalísimo Francisco Franco which expressed the need for a Panzer I (or negrillo, as their Spanish crews called them) with a 20-millimeter gun. Ultimately, the weapon chosen was the Breda Model 1935, due to the simplicity of the design over competitors such as the German 2 cm FlaK 30. Furthermore, the 20 mm Breda was capable of perforating 40 millimeters of armor at 250 meters (1.57 in at 275 yd), which was more than sufficient to penetrate the frontal armor of the T-26. Forty Italian CV.35 light tanks had been ordered with the Breda in place of their original armament, this order was canceled when it was thought adaptation of the same gun to the Panzer I would yield better results. Prototypes were ready by September 1937 and an order was placed after successful results. The mounting of the Breda in the Panzer I required the original turret to be opened at the top and then extended by a vertical supplement. Four of these tanks were finished at the Armament Factory of Seville, but further production was canceled as it was decided sufficient numbers of Republican T-26 tanks had been captured to fulfill the Nationalist leadership's request for more lethal tanks. The Breda modification was not particularly liked by German crews, as the unprotected gap in the turret, designed to allow the tank's commander to aim, was found to be a dangerous weak point. In late 1938 another Panzer I was sent to the Armament Factory of Seville in order to mount a 45 mm gun, captured from a Soviet tank (a T-26 or BT-5). A second was sent sometime later in order to exchange the original armament for a 37-millimeter Maklen anti-tank gun, which had been deployed to Asturias in late 1936 on the Soviet ship A. Andreiev. It remains unknown to what extent these trials and adaptations were completed, although