Chainmail (game)

Chainmail was created by miniatures gaming enthusiasts in the late 60's in Wisconson. These friends, led by Gary Gygax & Jeff Perran, codified a set of rules that they'd been using for minitures battles similar to  Warhammer Fantasy. Gary co-published these rules with Don Kaye, co-founding the company  Tactical Studies Rules.

Gary created a scenario of individuals heros, instead of groups in formation, moving thru an underground "dungeon". This became so popular, that the group developed a set of rules for these "characters" that allowed them to evolve from session to session. This led Gary and Dave Arneson to develop what was to become  Dungeons & Dragons