Ernest Gary Gygax was an American writer and game designer, best known for co-creating the pioneering role-playing game Dungeons & Dragons (D&D) with Dave Arneson. Gygax is generally acknowledged as one of the fathers of the tabletop role-playing game. In the 1960s, Gygax created an organization of wargaming clubs and founded the Gen Con gaming convention. In 1971, he helped develop the Chainmail miniatures wargame, which was based on medieval warfare. He co-founded the company Tactical Studies Rules (TSR, Inc.) with childhood friend Don Kaye in 1973. The following year, he created Dungeons & Dragons with Dave Arneson, expanding on his work on Chainmail and including elements of the fantasy stories he loved as a child. He also founded the magazine The Dragon in the same year, to support the new game. In 1977, Gygax began work on a more comprehensive version of the game, called Advanced Dungeons & Dragons. Gygax designed numerous manuals for the game system, as well as several pre-packaged adventures called "modules" that gave a person running a D&D game (the "Dungeon Master") a rough script and ideas on how to run a particular gaming scenario. In 1983, he worked to license the D&D product line into the successful Dungeons & Dragons cartoon series. Gygax was married twice and had six children. In 2004, he suffered two strokes, narrowly avoided a subsequent heart attack, and was then diagnosed with an inoperable abdominal aortic aneurysm, from which he died in March 2008.