A flintlock is a type of firearm mechanism that uses a flint to ignite gunpowder. Developed in the early 17th century, it replaced earlier matchlock designs and became popular for its reliability and ease of use. The flintlock mechanism consists of a hammer that strikes a piece of flint against a steel frizzen, creating sparks that ignite the powder in the pan, leading to the firing of the bullet. Flintlocks were widely used in military and civilian firearms until the mid-19th century, when they were gradually replaced by more advanced mechanisms like the percussion cap. Notable examples of flintlock firearms include the Brown Bess musket, which was used by British troops during the 18th and early 19th centuries.