Actually the advent of the firearm, along with the ability of the yeomen to stand against the armored noble, probably helped usher in the era of the rights of everyman, rather than just the rights of nobles. While militia like entities did exist before firearms, it was only the advent of the relatively inexpensive and easy to use firearm, that made mininmally trained militia armies effective on the battlefield. One they had the guns, how could the fuedal Lords continue to subjegate them? Being civilized is all fine and good, but being free is much better.
The people, sir, are a beast. Liberty is not found in the herd--for it represents the greatest threat to freedom. That is why we catalogue our sacred rights, the right to Keep and Bear arms among them, in a Bill of rights, where they can be secure from the encroachments of transient majorities.