The Wheellock was mentioned by Leonardo Da Vinci at the end of the 15th Century. The first models were built in Germany in the 1520's. In the case of the Wheellock, it is a piece of Iron Pyrite rather than Flint that is clamped in the dog.
It was the appearence of the Wheellock that lead to the first practical pistols to be constructed. While having one of the fastest ignition times until the advent of the Percussion Lock, the complicated mechanism and prohibitive cost meant that it would not supplant the Matchlock in military arms. In the civilian use, the Wheellock would continue to be made until 1829 by LePage.