Team Fortress 2
The original Team Fortress was developed by Robin Walker and John Cook. This early version of Team Fortress was a free mod for the 1996 PC game Quake. In 1998, Walker and Cook were employed by Valve. At the time, Valve just released its first game, Half-Life. Valve began developing Team Fortress 2 as a separate retail game using one of Valve's own game engines, GoldSrc. In 1999, Valve released Team Fortress Classic, a port of the original Team Fortress, as a free Half-Life mod. Team Fortress Classic was developed using the publicly available Half-Life software development kit as an example to the community and industry of the flexibility of the Half-Life game.