First lets start off by defining what eSports (professional gaming). eSports can be defined as a form of sports where the primary aspects of the sport are facilitated by video games; the input of players and teams compete against each other for prizes (most are cash).
1980
Atari were the first to host a video game tournament with the game Space Invaders. It brought more than ten thousand people
to watch the tournament live. This put the first nail in the tent in starting something that will become one of the biggest sports ever.
1990
With the growing popularity of gaming tournaments, other companies started to host their own tournaments. Companies like Blockbuster and Nintendo sponsored World Championships which started involving a lot more countries instead of just the United States. They even hosted other tournaments for childern to start competing in at a young age.
1990-1999
The 1990's saw a rise in the popularity of PC Gaming. This is what started the first "true eSports competitions." The first eSport competition was in 1997 for the first-person shooter (FPS) Quake. The prize for first place was a Ferrari that was owned by the lead developer of Quake. In the following weeks, the Cyberathlete Professional League was the first major gaming league ever formed. They hosted a tournament where there was an actual cash prize of $15,000. Most games between 1990 and 1999 were FPS, Arcade Games, and sports games. It wasn't until almost the end of the century where RTS (real time strategy) games became popular.