The original Team Fortress, a QuakeWorld mod designed in 1996 by Robin Walker, John Cook, and Ian Caughley, was a huge hit, offering team- and class-based online multiplayer action that was unlike anything gamers experienced in any other Quake mod. Players found themselves taking on the roles of important team positions, such as the medic, the engineer, the soldier, the sniper, and five other unique classes. Each with their unique strengths and weaknesses, players had to actually work together to reach a common goal: defeat the other team.
John Cook and Robin Walker soon began work on Team Fortress 2, while the game was put on hold to work on a revamp of the original mod after signing on with Valve. Called Team Fortress Classic (or TF 1.5), the revised mod took advantage of Valve's newer GoldSrc and became a free mod for Half-Life in 1999. Team Fortress 2 didn't see the light of day until 2007, demolishing growing doubts that--like Duke Nukem Forever--it had become vaporware.