An immediate predecessor of Dungeons & Dragons was a set of medieval miniature rules written by Jeff Perren. These were expanded by Gary Gygax, whose additions included a fantasy supplement, before the game was published as Chainmail. When Dave Wesely entered the service in 1970, his friend and fellow Napoleonics wargamer Dave Arneson began a medieval variation of Wesely's Braunstein games, where players control individuals instead of armies. Arneson used Chainmail to resolve combats. As play progressed, Arneson added such innovations as character classes, experience points, level advancement, armor class, and others. Having partnered previously with Gygax on Don't Give Up the Ship!, Arneson introduced Gygax to his Blackmoor game and the two then collaborated on developing "The Fantasy Game", the role-playing game (RPG) that became Dungeons & Dragons, with the final writing and preparation of the text being done by Gygax.