After World War I, Germany was forbidden by the treaty of Versailles to posses or produce tanks. However, during the 1920s a variety of weapons, including AFVs, were developed in secret and, with the connivance of the Soviet Union, were tested at Kazan in Russia. After the rise of Hitler, rearmament was accelerated and plans were laid for the development of purpose-built battle tanks that eventually emerged as the Panzers III and IV. As an interim measure, a vehicle was required for the training of the nascent armored forces and, in 1933, prototypes of a simple, cheap and easy to manufacture tank were invited from a number of firms. A design by Krupp, based on the Carden-Lloyd tankette, was selected and production began in 1934. Later designated Panzerkampfwagen I it was 13ft long and weighed 5.4 tons, with a crew of two. Armament was two 7.92mm machine guns and 3,125 rounds of ammunition were carried. In 1935 a further stopgap machine, the Pzkpfw II, was produced, weighing 10 tons and armed with a 20mm Kwk 30 gun with a co-axial 7.92mm machine gun.
