During the early 15th century appeared a simple matchlock device called a serpentine which was essentially an "S" shaped piece of metal with a central pivot attached to the side of the gun. By pulling on the bottom half of the pivot you lowered the upper half, which held a burning slow match (hemp or cotton rope soaked in saltpetre) into a pan containing a priming charge of powder to fire the gun. The firearm that utilized this device was known as the arquebus. The operation of the serpentine lock arquebus is shown in the animation below.
Arquebus with Snapping Matchlock*
Arquebus with Sear Lock Matchlock*
Despite these advances it would not be until the battle of Pavia, Italy in 1525 that the arquebus's full potential would be realized. During the battle 3000 arquebusiers, protected by pikemen, dealt a devastating defeat to the French by killing over 8000 of their armored cavalrymen and thus ending the mounted knights domination over Europe's battlefields.