In 1969 and 1970, friends Gary Gygax and Dave Arneson regularly played a miniature based Napoleonic tabletop wargaming system at the Lake Geneva Wargaming Conference (GenCon). However, their games in those years became smaller and soon revolved around special individual soldiers and their stories. In 1970, they transferred the concept to a medieval setting because Gygax, a Dark Age enthusiast, found the appropriate miniatures. They used the rules from the game “Chainmail”, which Gygax had written with a friend, to resolve individual actions. Together, they developed a generic fantasy wargaming system that focused solely on individuals and their stories instead of armies and groups of soldiers.

In 1971, Arneson added a storytelling role to the referee, a fixture in the contentious world of tabletop wargaming, who was usually a neutral observer and adjudicated disputes. The “Game Master” guided the players on quests and played the monsters. At Gencon that year, Arneson and a few of his friends ran Gygax and a few of his friends through a “six level dungeon” where the big bad at the end was a “troll in magic armor”. Gygax was enamored with the “funhouse” aspect of the game and immediately saw the creative and commercial possibilities. Over the next year Arneson and Gygax developed the rules for their game, which then went by the working title “Blackmoor”, and created a fictional and vaguely Tolkein-esque setting centered on “The Great Kingdom” for use with the system.

In December 1973, they formed Tactical Studies Rules with two other friends to self-publish their new tabletop gaming system because no established gaming company was interested. The first run of the newly named “Dungeons and Dragons” was only 1000 copies that were assembled in Gygax’s garage. On 26 January 1974, Gary Gygax invited everyone over to his house for the first session of Dungeons and Dragons which only became available to the public that day.