This was posted online from the supposed foreword of the Holmes set. It was an early hit entering those search terms....
https://www.americanroads.us/DandD/DnD_Basic_Rules_Holmes.pdf
If quoting here is not allowed I will happily edit it out.
"ONCE UPON A TIME, long, long ago there was a lit- tle group known as the Castle and Crusade Society. Their fantasy rules were published, and to this writer's knowledge, brought about much of the current interest in fantasy wargaming. For a time the group grew and prospered, and Dave Arneson decided to begin a medieval fantasy campaign game for his active Twin Cities club. From the map of the "land" of the "Great Kingdom" and environs — the territory of C & C Society — Dave located a nice bog wherein to nest the weird enclave of "Blackmoor," a spot between the "Giant Kingdom" and the fearsome "Egg of Coot." From the CHAINMAIL fantasy rules he drew ideas for a far more complex and exciting game, and thus began a cam- paign which still thrives as of this writing! In due course the news reached my ears, and the result is what you have in your hands at this moment."
E. Gary Gygax 1973