Jean Le Page (1779–1822) was a well-known French gunsmith.
This followed the discovery of fulminates by Edward Charles Howard in 1800.
Between 1807 and 1810, Le Page invented a new way to fire portative firearms, by using the mercury fulminate priming medium to be fired by the blow of a percussion hammer.
[2] The new mechanism used a magazine filled with fulminate primer, which would deliver a small amount of priming powder near the gun breech every time the magazine was cocked.
[2] Since the fulminate powder was highly sensitive to humidity, methods of coating the fulminate in varnish were developed,[2] as well as methods of encasing the fulminate culminating with the invention of the percussion cap by François Prélat in 1818 and Deloubert in 1820.