In 1974, a new game developer attempted to pitch his concept to Avalon Hill. Gary Gygax and Dave Arneson had co-developed a new type of co-operative game that used role-playing. But when Gygax pitched "Dungeons & Dragons" to AH, the largest company in wargaming did not understand the concept of role-playing, and turned down his offer. Gygax was forced to form TSR Inc in order to self-publish his game. In less than five years, TSR would be the dominant player in the new RPG market.