The Matchlock was the first firearm to have a trigger mechanism for firing. Matchlock refers to the type of lock mechanism used for igniting the gun's powder.
A further development of flashpan technology, the matchlock gun held a wick or slow match in a vice at the end of a small lever arm. Upon pulling a trigger the lever arm dropped down, lowering the lighted wick into the flashpan and firing the weapon. This design removed the need to lower a lighted wick into the flashpan by hand and made it possible to have both hands free to keep a firm grip on the weapon at the moment of firing.
An inherent weakness of the matchlock was the necessity of keeping the wick constantly lit. Being the sole source of ignition for the powder, if the wick was not lit when the gun needed to be fired, the mechanism was useless, and the weapon became little more than a fancy club. This was chiefly a problem in damp weather, when wet wicks were difficult to light and to keep burning. Another drawback was the wick itself. At night, the wicks would glow in the darkess, potentially giving away the carrier's position. It was also quite dangerous when a group of men were speedily handling large quantities of gunpowder along with lighted wicks. Chances for accidents were many.
Despite the appearance of better ignition systems, such as that of the wheellock and the flintlock, the low cost of production, simplicity, and high availability of the matchlock kept it in use well into the 1700s. It was eventually completely replaced by the flintlock as the footsoldier's main armament.