Musketeers were soldiers armed with muskets and play a transitional role in infantry combat between infantry armed with traditional melee weapons and the first generation of firearms. They were the precursor to riflemen, which began to appear around the 1850s with the arrival of mass-produced firearms.

Muskets were difficult weapons to wield in the early days. Muskets were built by hand by craftsmen, and were expensive and not standardized. They were notoriously cranky to use, and rain could make some muskets completely useless. They had to be hand loaded, which took time and left the musketeer vulnerable. Musketeers were known for carrying additional infantry weapons like lances and swords.

The first military units purpose built around the musket appeared in the armies of the Chinese Song Dynasty in the 12th century. As muskets spread, formations of these soldiers began to appear in India, and Europe. The most famed musketeers were formed by Louis the XIII of France in 1622. The iconic British Redcoats were essentially musketeers until their muskets were replaced by rifles.