Team Fortress is a team- and class-based online multiplayer video game mod originally based on the first person shooter Quake, made by id Software. Team Fortress was designed and written by Robin Walker, John Cook and Ian Caughley in 1996. The mod's gameplay has caught on with a large following of fans, which has spurred many developers to create similar gamemodes on other engines. In August 1999, after the development team was hired by Valve, Team Fortress was ported to Valve's GoldSrc engine in the form of Team Fortress Classic. An official sequel developed by Valve Corporation was hinted at for many years, and was finally released in October 2007 as Team Fortress 2.