At ArneCon I was able to play in Dave Arneson's Medieval Battle (run by his friend Bill Hoyt) and in Dave Megarry's DUNGEON! (run by Dave himself). Dave, in turn, showed me his old character sheets from the original Blackmoor RPG campaign. 1. Dave Arneson's Medieval Battle seems to have been inspired by or house ruled from or related to Chainmail but it wasn't identical. The setting, map, and factions of this battle later evolved or were repurposed into Blackmoor. As a game, it was beer-and-pretzels, but as a scenario it had PvP RPG elements that were notable. 2. Dave Megarry's DUNGEON! explicitly used the characters, monsters, and combat system from the Chainmail fantasy supplement. DUNGEON! predated OD&D by over a year; Megarry actually introduced Gygax to the concept in a joint meeting with Arneson and Gygax. 3. Dave Megarry said that he, not Arneson or Gygax, was the originator of the idea that deeper dungeon levels were mathematically linked to harder monsters with more treasure. He had studied economics in college and explained how he had developed the dungeon system based on expected return and risk. (Me: "I KNEW IT! IT WAS ABOUT ECONOMICS ALL ALONG") 4. The Blackmoor character sheets that Megarry showed me did not resemble Chainmail or OD&D in the slightest. They had dozens of attributes and skills per character. He couldn't really explain the rules because they were "all in Arneson's head." Arneson and Megarry saw the two (Blackmoor and DUNGEON!) as entirely distinct. I left the convention somewhat abashed that I had overlooked David Megarry's contribution to the hobby. He is the grandfather, not just of core aspects of the D&D gameplay loop we now take for granted, but of the entire boardgame genre of Descent, Gloomhaven, etc.