A pistol is a small gun that can be held and fired with one hand. Firearms had been in use for centuries before the handheld gun became practical. Until the 16th century, soldiers had to ignite the gunpowder by hand, a time-consuming and dangerous undertaking even with the largest cannon. In the early 1500s, however, the wheellock, an ignition mechanism that could be installed inside the firearm, was invented. Similar to the ignition system found in cigarette lighters today, the wheellock consisted of a steel wheel revolving against a flint, producing a spark to set off the powder. Handguns were soon in production and have remained popular ever since because they can be carried easily and leave one hand free to wield another weapon. Although it is not clear who was the first to develop a pistol, the first designs of about 1540 are commonly credited to Caminelleo Vitelli...