As most of 'you people' know I am the foremost historian on this blog. For the life of me, however, I cannot drill down to the time when left-handed people became a thing. Nearest I can tell it was sometime in the 1940's. About the time WWII ended.
Theory: they were invented to offset us right-handers. Kinda like how car manufacturers started putting the gas tank on different sides of the car, so gas stations could flow a bit easier.
Thoughts?