Development of the tank began in the summer of 1915. The idea was to combine the caterpillar tracks of an American tractor with an iron-clad machine that could straddle the enemy's trenches. By spring of the following year a working model was available
for testing. Manned by a crew of four, the 30-ton weapon's armament consisted of two cannons mounted on its sides. It lumbered along at three miles an hour. The new weapon made its battlefield debut on 15 September 1916 when fifty of the machines
joined the Battle of the Somme in a third attempt to attack and break through the German defences. Their presence shocked the enemy, but their practical impact was minimal due to a lack of effective tactics and numerous mechanical failures. But, the door to the future was opened and the first step taken in the development of a weapon that would dominate the battlefield of future wars.