**Tank** , any heavily armed and armoured combat vehicle that moves on two endless metal chains called tracks. Tanks are essentially weapon platforms that make the weapons mounted in them more effective by their cross-country mobility and by the protection they provide for their crews. Weapons mounted in tanks have ranged from single rifle-calibre machine guns to, in recent years, long-barreled guns of 120- or 125-mm (4.72- or 4.92-inch) calibre. This article discusses the development of tanks from the beginning of the 20th century to the present. For articles on related military platforms, _see_ amphibious assault vehicle and armoured vehicleEarliest Developments The use of vehicles for fighting dates to the 2nd millennium BCE, when horse- drawn war chariots were used in the Middle East by the Egyptians, Hittites, and others as mobile platforms for combat with bows and arrows. The concept of protected vehicles can be traced back through the wheeled siege towers and battering rams of the Middle Ages to similar devices used by the Assyrians in the 9th century BCE. The two ideas began to merge in the battle cars proposed in 1335 by Guido da Vigevano, in 1484 by Leonardo da Vinci, and by others, down to James Cowen, who took out a patent in England in 1855 for an armed, wheeled, armoured vehicle based on the steam tractor. But it was only at the beginning of the 20th century that armoured fighting vehicles began to take practical form. By then the basis for them had become available with the appearance of the traction engine and the automobile. Thus, the first self-propelled armoured vehicle was built in 1900 in England when John Fowler &; Company armoured one of their steam traction engines for hauling supplies in the South African (Boer) War (1899–1902). The first motor vehicle used as a weapon carrier was a powered quadricycle on which F.R. Simms mounted a machine gun in 1899 in England. The inevitable next step was a vehicle that was both armed and armoured. Such a vehicle was constructed to the order of Vickers, Sons and Maxim Ltd. and was exhibited in London in 1902. Two years later a fully armoured car with a turret was built in France by the Société Charron, Girardot et Voigt, and another was built concurrently in Austria by the Austro-Daimler Company. To complete the evolution of the basic elements of the modern armoured fighting vehicle, it remained only to adopt tracks as an alternative to wheels. This became inevitable with the appearance of the tracked agricultural tractor, but there was no incentive for this until after the outbreak of World War I. A tracked armoured vehicle was proposed in France as early as 1903 but failed to arouse the interest of military authorities, as did a similar proposal made in England in 1908. Three years later a design for a tracked armoured vehicle was rejected by the Austro-Hungarian and then by the German general staffs, and in 1912 the British War Office turned down yet another design. Best NDA Class In Pune ( Dignitary )