With each genre of gaming there is a line that one can follow through history, to times before they became what they are today or even existed. However let’s stick to table-top role playing games. The idea of a TT-RPG is to create a mythological or futuristic creature and assume the characteristics of that character, as the Game Master/ Dungeon Master/ Storyteller paints a picture for the players. That picture is the world the characters must explore and interact with to continue the assumed creatures main goal.
Knowing this it might become apparent that these kind of activities happened long before modern times. A more well known system for what was just explained are plays or nowadays TV shows. The director creates the world and the actors explore and interact with the world while the audience is a passenger on the journey. There are also other similar games played out among certain groups such as mock training for jobs or military organizations. These all came long before 1974 with the initial release of modern day TT-RPGs Dungeons and Dragons.