In the days of old when knights were bold murder was pretty common. In 13th century Europe, the rate was 22.68 per 100,000 rising to 40.79 per 100,000 by the 15th century. Carlisle Moody: Handguns Stop Murders
It was as though every place in Europe was Chester, Pa. Well, maybe not that bad. Figure Detroit or New Orleans.
But then something happened. In the 16th century the rate tumbled back to 20.28 per 100,000.
Carlisle Moody of the College of William & Mary says that the year the trend changed was 1505 and what happened was the handgun, namely the wheel lock pistol which by that year had become common enough to make a social impact.
The pistol put the little guy (and gal) on a equal footing the big, strong, armor-plated club/knife/ax wielding thug.