User blog comment:Master Sima Yi/Assassinews 19-03-'14 – Two Assassin's Creeds for 2014?: Unity and Comet/@comment-13471981-20140603155847/@comment-4829046-20140603165515

Well... they use this info as the base for the fiction -

"The invention of the wheel-lock in Europe can be placed at about 1500. There is a vocal group of scholars who believe Leonardo da Vinci was the inventor. Drawings made by Leonardo of a wheellock mechanism date (depending on the authority) from either the mid-1490s or the first decade of the 16th century. However, a drawing from a book of German inventions (dated 1505) and a 1507 reference to the purchase of a wheellock in Austria may indicate the inventor was an unknown German mechanic instead."

So yeah, that's kinda where it goes, but I'm taking it in game perspective. The way Ezio used the thing, both regular shooting and kill animations.