So long ago, we do not have exact records. The first primitive cannon were from about 1000 years ago. In the 1200's, short firearms called "hand cannon" were carried into battle.
No.
Italy
Italy and USA
Yes, they are.
If you're asking when were handguns first made, the answer is the 1400s. The first handguns were basically small hand-cannons.
Both.
handguns and long guns
The brands that are well made are not. There are some cheap crappy handguns that are prone to breakage, but that's been the case ever since cheap crappy handguns have been made, even before polymer was used.
High Standard was one
Nothing in my references on Dixon handguns, except the Dornaus & Dixon Bren 10, made in California by Dornaus & Dixon.
Dozens of makers made them in the 70s
Many handguns made in this caliber.