Anti-tank warfare originated from the need to develop technology and tactics to destroy tanks during World War I. Since the Triple Entente developed the first tanks in 1916 but did not deploy them in battle until 1917, the German Empire developed the first anti-tank weapons. The first developed anti-tank weapon was a scaled-up bolt-action rifle, the Mauser 1918 T-Gewehr, that fired a 13mm cartridge with a solid bullet that could penetrate the thin armor of tanks of the time and destroy the engine or ricochet inside, killing occupants. Because tanks represent an enemy's greatest force projection on land, military strategists have incorporated anti-tank warfare into the doctrine of nearly every combat service since. The most predominant anti-tank weapons at the start of World War II in 1939 included the tank-mounted gun, anti-tank guns and anti-tank grenades used by the infantry, as well as ground-attack aircraft.