Modern gun control started with the assassination of JFK.
If you want to look before WWII then the violence surrounding prohibition sparked legislation. That brought us the National Firearms Act.
As has been mentioned there has been different types of weapons control for centuries before firearms. From keeping knightly weapons out of the hands of peasants to keeping firearms out of the hands of minorities, much of those laws were in support of an entrenched power structure.
Current entrenched power structure no longer use firearm restrictions to keep a segment of society under control. There are a host of other measure for keeping the peasantry in their place.
Most gun control advocates claim a compelling societal harm done by firearms. They feel that restrictions on firearms makes society and citizens safer.
If you visit the Brady web site they can give your their arguments.
http://www.handguncontrol.org/?q=bradycenter
The Bray campaign itself was instigated by the attempted assassination of Ronald Reagan and the wounding of Jim Brady.