Who invented the musket in the 1700s?

The musket actually emerged in the 16th century in Spain. The Frenchman Marin le Bourgeoys is the most likely inventor of the first true flintlock musket; that development took place in the early 17th century. Prior to the invention of the flintlock musket, the weapons were typically matchlocks.

The flintlock was the second stage in the musket's development. By the early 19th century, percussion locks had replaced flintlocks. The original matchlock musket was a variation on the harquebus although larger in size. The first muskets were quite large, generally requiring more than one person to handle them and a portable rest for firing.