[Tom the Fish]

I've searched the internet for this several times through the years but I've never found an answer.

For as long as I've followed MLB baseball, the roster size has been 25 players, with the roster being expanded to 40 players on September 1st. I can't imagine it has always been this way, especially back when less pitchers were needed. Were there roster size rules pre-1900s? If so, what were they? If there weren't rules, when were the introduced? Were they always 25 men? When were expanded rosters allowed? Was it always up to 40? When did the 40 man roster appear with the waiver rules?

Thanks,
Tom