We got our first introduction to Snoke in Episode 8. But both him and the First Order’s rise were possibly influenced by Knights Of The Old Republic.
Star Wars fans know that after the Emperor had died in Return Of The Jedi, the galaxy came together to form the New Republic. Mon Mothma was the one that spearheaded the New Republic and ended up being one of the Rebellion’s first leaders. While this was happening, the Empire was trying to rebuild itself. Once all Imperial Officers were declared war criminals by Mon Mothma, they escaped to the Unknown Regions, on the outskirts of the Outer Rim.
Now, there is a theory that Snoke and The First Order could have gotten their influence from The Knight Of The Old Republic, but more specifically from The Rakata, which is an alien species from BioWare’s Knights Of The Old Republic video game. But not only does it seem like that is were Snoke got his powers from, but this could also become canon.
Given the story in Knights Of The Old Republic, and that Snoke has a unique connection to the Dark Side, he could share his knowledge with his generals. The major problem here though: Knights Of The Old Republic isn’t canon anymore. However, the Story Group at Lucasfilm has been really good in recent years to make things from Knights Of The Old Republic canon. So for this to become canon wouldn’t be a major surprise. But it would be nice to get more characters and backstories from Knights Of The Old Republic in Star Wars canon.