Laws don’t dictate morality and entrenching “being scared” as the basis for self-defense laws gives everyone far too much leeway in “being scared” of the black kid with his hood up, or the delivery driver that you got too high to remember, or somebody answering the door to an unindicated police raid with a legal gun in their hand.
From Wikipedia
Around the late 14th century in Europe, smaller and portable hand-held cannons were developed, creating in effect the first smooth-bore personal firearm.