Saturday, November 30, 2019

OD&D v3: The Underworld & Wilderness Adventures

The third volume of the original D&D rules is divided into three main sections.  The Underworld (covering dungeons), the Wilderness (including rules for establishing a domain), and rules for mass combat (land, aerial, and naval).

D&D volume 3: The Underworld & Wilderness Adventures (Jan 1974)

"The Underworld" provides rules for dungeon exploration.  There is a sample cross section of levels, a sample map of a level, a section on dungeon design, movement and exploration, wandering monster tables, and an example of play.

Much of "The Underworld" section was incorporated into the Basic Rulebook edited by J. Eric Holmes (1977), and again in revisions edited by Tom Moldvay (1981), and Frank Mentzer (1983), creating an association between "Basic" D&D and the dungeon adventure.

"The Wilderness" section involves overland exploration, castles/jousting, wandering monster tables, construction of castles/strongholds, specialists, men-at-arms, player/character support and upkeep, and baronies/domain management.

Jousting Matrix, from Chainmail

Rules for wilderness adventures, construction of castles/strongholds, and specialists/men-at-arms were included in the "Expert" Set (Cook/Marsh, 1981), while tournaments/jousting* and "dominion administration" became part of the "Companion" Set (Mentzer, 1984).

*see also "Chainmail Revisited: Jousting in D&D" by Jon Pickens (The Dragon #17, Aug 1978)

The final section of The Underworld & Wilderness Adventures provides rules for mass combat (Chainmail), aerial combat ("Battle in the Skies" or BITS, based on Mike Carr's "Fight in the Skies"), and naval combat (including special suggestions for monsters in naval adventures).

Mass combat was revisited in the later OD&D supplement "Swords & Spells" (1976).  The "Companion" Set introduced the "War Machine" rules for resolving mass combat without miniatures, while the later "Battlesystem" boxed set (1985) provided new rules for miniatures.

Illustration from Dave Arneson's "The First Fantasy Campaign" (1977)

Rules for aerial combat were derived from Arneson's "Battle in the Skies", demonstrated at Gary Con XI, this past March.  The "Secrets of Blackmoor" blog recently discussed the complexities of the "relative movement system" chart, here.

Waterborne adventures, including combat at sea, were described in the "Expert" Set (Cook/Marsh, 1981).  Many of the Expert modules involved seafaring (notably X1 "The Isle of Dread", in addition to X6, X7, X8, X9), although focused mainly on seaborne exploration.

Additional campaign rules include rumors, information, and legends; the "angry villager" rule; other worlds; healing wounds; and the passage of time.

Sunday, November 24, 2019

OD&D Dragons: On the Origin of Species

OD&D vol 2: Monsters & Treasure contains a lot of information regarding the different types of dragons, including rules for subdual.  I was always intrigued by the taxonomy of dragons in D&D, although was unaware of the origin of the different colored species.

The red dragon, (Draco Conflagratio, or Draco Horribilis), is clearly modeled after the dragon Smaug from Tolkien's "The Hobbit", and was previously described in Chainmail, while the other colors were only briefly mentioned (white, black, blue, green, and purple/mottled).

In Jon Peterson's Playing at the World, we learn that Gary Gygax wrote a number of articles entitled "Grayte Wourmes" on the different types of colored dragons, for a variant postal "Diplomacy" fanzine Thangorodrim, published by the International Federation of Wargamers.

Cover of Thangorodrim, vol 1, no 2 (June, 1969).  The source of the dragon is immediately recognizable to anyone familiar with The Voyage of the Dawn Treader (1952) by C.S. Lewis

Thangorodrim #3 describes Draco Articus, the "Arctic Dragon" a white dragon with a "chilling breath" weapon:
Perhaps the rarest of the Great Worms is the Arctic Dragon, or "Frost Breath."  Unlike others of his kind, this large white worm inhabits only the coldest regions of the far north and has no internal fire.  Draco Articus seeks glaciers in which to dwell and if the temperature remains cold enough they will sleep therein for very long period of time, only awakening to feed when stimulated by warmth.  The Arctic Dragon will attack any living creature on sight, often including others of his own species.  Their main weapon is a chilling breath (which will immediately freeze boiling water).  All recorded specimens have only a single head, are up to 100 feet in length, weigh eight tons, and otherwise conform to Dragons in general (wings, fangs, claws, etc.)...  Articus does not usually hoard and is of low intelligence.

Subsequent installments covering the black, green, blue, and purple (mottled) dragon followed.  (Jon Peterson, Playing at the World, 2.5.2 Draco Horribilis).

Copies of Thangorodrim are obtainable on Internet Archive and make for some fascinating reading.  I've reproduced the sections describing the "Grayte Wourmes", below:

Thangorodrim vol 1, no 5 (Nov, 1969)

Thangorodrim vol 1, no 6 (Mar, 1970)

Thangorodrim vol 1, no 8 (July, 1970)

Thangorodrim vol 1, no 9 (Aug, 1970)

In Dave Arneson's Blackmoor campaign, Richard Snider described three types of dragon (gold, brown (similar to red) and green (no breath weapon).  Snider's "Golden" dragons can breathe fire, and are very intelligent, as described in Monsters & Treasure.

The feared Purple Worm (or "Wyrm") became more of a giant earthworm than a dragon.  The entry for sea monsters follows that for purple worms in Monsters & Treasure, which are said to be "equal in size to a Purple Worm" but twice or three times the size are possible.

Illustration from OD&D vol 2, Monsters & Treasure

Last, but certainly not least, the Dragon Turtle is depicted in Monsters & Treasure, but only described in the "Special Suggestions for Monsters in Naval Adventures" section, on page 34 of OD&D vol 3, The Underworld & Wilderness Adventures.

Saturday, November 23, 2019

OD&D v2: Monsters & Treasure

Much of the Chainmail fantasy supplement was incorporated into the OD&D rules.  Some of the material is verbatim, while other parts were expanded upon.  Additional sections were derived from Dave Arneson's Blackmoor campaign.

D&D volume 2: Monsters & Treasure (Jan 1974)

The second volume covers monster descriptions (with a reference table), treasure types, explanations of magic items (including "super swords"), saving throws, a short description of artifacts, and treasure (precious metals, gems, and jewelry).

Most of the monsters appeared previously in Chainmail.  Some categories were expanded - such as men (bandits, berserkers, brigands, dervishes, nomads; buccaneers, pirates; cavemen; mermen), giants (hill, stone, frost, fire, cloud), and sprites (nixies, pixies, dryads).

Hobgoblins and gnolls are added, the latter described as "a cross between gnomes and trolls (...perhaps, Lord Dunsany did not really make it all that clear)"
The creature described as the gnole first appeared in 1912, in Lord Dunsany's story "How Nuth Would Have Practised His Art upon the Gnoles", and reappeared in Margaret St. Clair's "The Man Who Sold Rope to the Gnoles".

Lord Dunsany's story gives little or nothing in the way of physical description of the gnoles, but they live on the edge of a sinister wood and watch intruders through holes bored in trees.  They are said to own emeralds of very large size.  In St. Clair's story, they also live on the edge of a wood, watch through holes bored in trees and prize emeralds, but a "senior gnole" is described as looking "like a Jerusalem artichoke" and, although he has feet, has tentacles rather than arms and no ears.  His eyes are small, red and faceted like a gemstone.
from the Wikipedia entry for "Gnoll"

Gygax later stated "The original gnoll was a strange critter in a (rather bad) novel that I wrote and was in part run in Dragon magazine's early numbers.  I didn't find that creature a suitable humanoid for the D&D game, so I revised gnoll into a hyena-like humanoid.  (I find hyenas most unappealing in all respects, including their stench)" in a forum post, here.

In 2014, Jon Peterson postulated that some of the additional monsters in Monsters & Treasure, such as the gorgon, might have originated from Ernst and Johanna Lehner's "A Fantastic Bestiary: Beasts and Monsters in Myth and Folklore" (1969).

"A Fantastic Bestiary" also includes entries for the "manticora" (note the spelling), and a section on "benign" monsters, including the centaur, the pegasus, and the unicorn (the monster reference table in Monsters & Treasure is subtitled "hostile and benign creatures").

Two additional creatures from Greek mythology were included, classified as a type of monster in D&D thereafter, namely Medusa and the Minotaur.

Jason fighting the Hydra, movie still from wikimedia commons

The dinosaur-like hydra was likely inspired by Ray Harryhausen's version from Jason and the Argonauts (1963), which also included skeletons.

Additional undead not appearing in Chainmail were the mummy and the vampire, likely based on Hammer Film Productions The Mummy (1959) and Dracula (1958) respectively, although vampires were already present in Blackmoor, inspired by the Dark Shadows TV show.

The gargoyle from French legend, as depicted in medieval architecture, is a creature not appearing in the Lehners' "A Fantastic Bestiary".

Finally, the so-called "Dungeon Clean-Up Crew" (ochre jelly, black (or gray) pudding, green slime, gray ooze, yellow mold, and the gelatinous cube) are unique to D&D, although inspired by monster films (ie. "The Blob", "The Green Slime").

Excerpt from Chainmail (1971), including mention of Excalibur and other "Super Swords"

In the treasure section, there are extensive rules for magic swords.  King Arthur's "Excalibur" and Elric's "Stormbringer" are clear inspirations.

Daniel Boggs explains the source of these rules, from Arneson's Blackmoor campaign, in his 2012 post Tracing Magic Swords.

Sunday, November 17, 2019

OD&D Magic-Users

Magic-Users in Chainmail have five levels of proficiency: Seers (added in the 3rd edition), Magicians, Warlocks, Sorcerers, and Wizards (corresponding to the 2nd, 6th, 8th, 9th, and 11th levels of experience in OD&D).  The greater their proficiency, the more spells they can use.

Spells in Chainmail have six levels of complexity, similar to Men & Magic.  Magic-users in Chainmail can attempt to cast spells of any complexity, regardless of their level, but with mixed chances of success (determined by a roll of 2d6).

It is also possible for magic-users to cast counter-spells, in order to negate each others magic.  Chainmail further states that "In order to cast and maintain any spell, a Wizard must be both stationary and undisturbed by attack upon his person".

"Wizards Fighting", from Men & Magic (1974)

In The Battle of Brown Hills (1971), the Lawful Magician of the Cairn could use lightning bolts, wizard light, and circle of protection, while the Chaotic Warlock Huldor ap Skree could use fire balls, phantasmal forces, spell of darkness, and conjuration of elementals.

In Dave Arneson's Blackmoor campaign, Pete Gaylord played the first magic-user, "The Wizard of the Wood", as documented in The Worlds First Wizard (2016).  Arneson used an alchemical-based magic system, as described in The First Fantasy Campaign (1977).

The sample character "Xylarthen" (Str 8, Int 11, Wis 13, Con 12, Dex 9, Cha 8)* in Men & Magic was the first "published" OD&D magic-user.  Gary Gygax favored a Vancian magic system, in which spells were "memorized" daily, and forgotten once cast.

*Rob Kuntz described "The Four Stones of Xylarthen" in his article "The Three Artifacts of the Demon Senders" published in Wargaming #2 (1977)

It's interesting to note which spells from Men & Magic derive from Chainmail (representing spells useful in large scale combat):
1st Level Spells:
1. Detect Magic - from "Detection" (II), Chainmail 1e
2. Hold Portal
3. Read Magic
4. Read Languages
5. Protection/Evil - from "Protection from Evil" (III), Chainmail 2e
6. Light - from "Wizard Light" (I), Chainmail 1e
7. Charm Person
8. Sleep

2nd Level Spells:
1. Detect Invisible - from "Detection" (II), Chainmail 1e
2. Levitate - "Levitate" (II), Chainmail 3e
3. Phantasmal Forces - from "Phantasmal Forces" (II), Chainmail 1e
4. Locate Object
5. Invisibility - a special ability of Wizards, from Chainmail
6. Wizard Lock
7. Detect Evil - from "Detection" (II), Chainmail 1e
8. ESP
9. Continual Light - from "Wizard Light" (I), Chainmail 1e
10. Knock

3rd Level Spells:
1. Fly
2. Hold Person
3. Dispell Magic - from the ability to cast a counter-spell, in Chainmail
4. Clairvoyance
5. Clairaudience
6. Fire Ball - missile equivalent to a large catapult, from Chainmail 1e
7. Lightning Bolt - missile equivalent to a heavy field gun, from Chainmail 1e
8. Protection/Evil, 10' r. - from "Protection from Evil" (III), Chainmail 2e
9. Invisibility, 10' r.
10. Infravision - a special ability of Wizards, from Chainmail
11. Slow Spell - "Slowness" (III), Chainmail 3e
12. Haste Spell - "Haste" (III), Chainmail 3e
13. Protection/Normal Missiles - a special ability of Wizards, from Chainmail
14. Water Breathing

4th Level Spells:
1. Polymorph Self - "Polymorph" (IV), Chainmail 3e
2. Polymorph Others
3. Remove Curse
4. Wall of Fire
5. Wall of Ice
6. Confusion - "Confusion" (IV), Chainmail 3e
7. Charm Monster
8. Growth/Plant
9. Dimension Door
10. Wizard Eye
11. Massmorph - from "Concealment" (III), Chainmail 1e
12. Hallucinatory Terrain - "Hallucinatory Terrain" (IV), Chainmail 3e

5th Level Spells:
1. Teleport - possibly inspired by the "Transference" spell, from Dungeon!
2. Hold Monster
3. Conjure Elemental - from "Conjuration of an Elemental" (V), Chainmail 1e
4. Telekinesis
5. Transmute Rock-Mud
6. Wall of Stone
7. Wall of Iron
8. Animate Dead
9. Magic Jar
10. Contact Higher Plane
11. Pass-Wall
12. Cloudkill - "Cloudkill" (V), Chainmail 3e
13. Feeblemind
14. Growth/Animal

6th Level Spells:
1. Stone-Flesh
2. Reincarnation
3. Invisible Stalker
4. Lower Water
5. Part Water
6. Projected Image
7. Anti-Magic Shell - "Anti-Magic Shell" (VI), Chainmail 3e
8. Death Spell
9. Geas
10. Disintegrate
11. Move Earth - from "Moving Terrain" (VI), Chainmail 2e
12. Control Weather
*Chainmail 1e (Guidon Games, 1971), 2e (Guidon Games, 1972), 3e (TSR, 1975 - after the publication of OD&D)

The final section in Men & Magic is "Books of Spells":
Characters who employ spells are assumed to acquire books containing the spells they can use, one book for each level.
The Holmes rulebook actually lists spells under "Book of First Level Spells", etc.  OD&D magic-users therefore possess a set of magical encyclopedias, which they use to study their spells, not a single customized spell book.

I prefer this system, starting PC magic-users with a single Book of First Level Spells.  Higher level Books of Spells can be found while adventuring, such as those used by enemy magic-users.  In fact, the thaumaturgist from the sample adventure in Holmes possesses two such books.

Saturday, November 16, 2019

OD&D v1: Men & Magic

I got hooked on the Holmes Basic Set as my re-entry to the hobby, back in 2009.  From there, I worked backwards to discover the OD&D rulebooks, using them as a natural extension to the Holmes Basic rules, when I started playing D&D with my son.

D&D volume 1: Men & Magic (Jan 1974)

The first volume broadly covers preparations for starting a campaign, including the various character classes/races, basic equipment, encumbrance, "alternative" (to Chainmail) combat system, saving throws, spell tables, magical research, and spell books.

Men & Magic also contains a section on "Character Alignment, Including Various Monsters and Creatures".  Each player character must choose between Law, Chaos, or Neutrality.  A table on page 9 lists creatures in three separate columns, one for each alignment:

Alignment Table, from Men & Magic.

A similar table appeared previously in the Chainmail rules:

"Alignment Table" from Chainmail.

Note the equating of "Good" with "Law" and "Evil" with "Chaos".  Neutral creatures are "non-aligned", rather than representing a "third" side of their own.  They can join forces with "Law" or "Chaos", or neither, although have a pre-disposition for "Law".

In a later section, Men & Magic states "Law, Chaos and Neutrality also have common languages spoken by each respectively."  In their earliest form, therefore, alignment languages were actual spoken languages, used among creatures of the same alignment.

If one regards the conflict depicted in The Battle of Brown Hills as a part of the prehistory of the OD&D setting, then "Law" and "Chaos" might be considered to represent ancient languages, now mostly forgotten, eventually becoming:
the special set of signs, signals, gestures, and words which intelligent creatures use to inform other intelligent creatures of the same alignment of their fellowship and common ethos
1e DMG, pg 24
As the cosmic conflict between Law and Chaos faded in subsequent editions of D&D, so too might the conflict have represented a primordial one in the PCs game world.  Perhaps, like the two sides of "the Force" in Lucas' Star Wars, discounted by some as mere legend.

Sunday, November 10, 2019

Dungeon! Rules Variants

Following the re-release of "Dungeon!" back in 2012, James Maliszewski interviewed David Megarry about the game's early development:
Gary made some changes to the board, insisting that there was an imbalance in the movement on the fourth level, but by and large the game has remained essentially as I designed it.  Gary did request player-to-player attack rules which I supplied but I insisted they be optional rules.  He added a few more optional rules like wandering monsters, but I viewed these as complications to the basic play
I've never played with either of these rules, but can see how they would make the game more interesting for experienced players.

Gygax went on to write two "Dungeon!" rules variant articles:

"Dwarves and Clerics in Dungeon!" in The Strategic Review #6 (vol. II, no. 1) February 1976
The Dwarf:  fights as an Elf, ignores traps, needs 10,000 gp to win
The Cleric:  fights as a Hero (or as a Superhero against undead monsters and evil characters), can use up to four hold monster or transference (teleport) spells, cannot be wounded or lose a turn unless "seriously wounded" (retreat one space, drop one prize, lose one turn - the same as a "light wound" in the 1980 version) although can still be killed, needs 20,000 gp to win
New Magic Itemsboots of speed (3rd level, can move up to 6 spaces/turn), magic armor (5th level, +1,500 gp, opponents "add +1 on rolls of 2-6, -1 on rolls 8-10 and 12, rolls of 7 or 11 not affected").
The convoluted rules for magic armor reflect the earlier version of the monster attack table (adding +1 on all monster attack rolls works as a suitable alternative, using the 1980 rules):

Combat Losing Table, from Dungeon! (1975)

The Strategic Review article also includes several new monsters and two new traps:
New Monsters:  basilisk, demon, dragon (white), elemental (earth, fire), evil priest, gnolls, harpy, manticore, orc, owl bear, spectre, wight, wraith, wyvern, zombie
New Traps:  anti-magic trap (lose all spells and magic items), fireball trap

"Hobbits and Thieves in Dungeon!" in The Dragon #1 (vol. 1, no. 1) June 1976
The Hobbit:  moves only 4 spaces/turn, fights as an Elf or a Hero (whichever needs the higher score to defeat a particular monster), more easily stunned (a score of 11 is treated as a 6 or 8 when rolling on the Player Losing Table), can use up to seven missiles (+2 on attack roll, may use from corridor, like spells), finds secret doors 1-3/d6, ignores traps, needs 10,000 gp to win

The Thief:  can move up to 6 spaces/turn, fights as a Hero (+1 on first attack, due to stealth and surprise), cannot be wounded in first round of combat (hides in shadows or climbs up out of reach), although can still be killed, steals prize on roll of 12 (avoiding combat, plus can move an additional 3 spaces), finds secret doors 1-2/d6, ignores traps (except slides), needs 30,000 gp to win

Expanding the types of characters possible to choose from invites the use of miniature figures to represent player pieces, as opposed to the colored pawns included with the game.  It would be fun to mock up monster and treasure cards to use with these variant rules, someday.

A few summers ago, my son and I experimented with these other character classes, also using the new magic items, monsters, and traps.  We found that the Hobbit enjoys clear advantages using its missile attacks, while still only requiring 10,000 gp to win.

Saturday, November 9, 2019


Back in the 1980s, my brother and I enjoyed playing "Dungeon!" when it wasn't possible to play D&D.  We had no idea that the game's origins actually predate D&D, or that it contributed to the latter's inception, not the other way around.

Cover to the Dungeon! fantasy boardgame (1980).  Illustration by Jim Roslof.  The warrior in the bottom left corner seems a homage to the Greg Bell swipe from the cover of the Greyhawk supplement (1975).

David Megarry was inspired by Dave Arneson's "Blackmoor" game to create a board game simulating a dungeon crawl.  He reflects on the history of "Dungeon!" in 40 Years of Dungeon! A conversation with David R. Megarry (2015), by The Fellowship of the Thing.

Megarry was introduced to Gary Gygax by Arneson at Gen Con III in 1970.  He and Arneson would famously drive to Lake Geneva in late 1972 to showcase "Blackmoor" and "Dungeon!" to Gygax.  Soon afterwards, Arneson and Gygax began collaborating on D&D.

Megarry started working on a second version of his game, naming it "The Dungeons of Pasha Cada" (1973), a copy of which came to light in 2011. The first edition of "Dungeon!" was published in 1975.  A revised edition followed in 1980 (the version we used to play).

Daniel Boggs has written about probable sources of inspiration for "Dungeon!" in Dungeon in the Womb of Strategos as well as the game's likely impact on the development of D&D in The Dungeon! Board Game as a Foundation of D&D.

I was fortunate enough to meet David Megarry in 2018.  For the past several years, Megarry has been running sessions of "Dungeon!" at Gary Con for multiple players, on the actual table that Arneson used to run his Blackmoor games.

David Megarry explains the development of his board game "Dungeon!" at Gary Con X (March, 2018).

David was a great host, and happy to chat about old times.  At the session's conclusion, each participant was given handmade monster and prize cards in a little slipcase as keepsakes (mine were for the 6th level - a red dragon and a ruby ring worth 4,000 gp).

Incidentally, when I asked him about the long corridor running along one side of the board, he told me that it was originally intended to line up with another game called "Castle", and that a third game "Kingdom" was also planned, presumably to simulate wilderness adventures.

The following year, my son signed up to play in one of Megarry's sessions.  My kids and I have enjoyed playing "Dungeon!" for years, and my son was looking forward to the experience.  Afterwards, he received a very special memento:

A copy of Megarry's First Dungeon (1972), reproduced with kind permission by David Megarry.

The map is a fascinating piece of the game's history.  It evokes a sense of mystery and adventure, although we were too awestruck to ask about any of its features.  Perhaps David can be enticed to share a few contextual details, at next year's Gary Con.

I recently stayed up late with one of my daughters, long after her sister went to bed, in her quest for the fabled 10,000 gp diamond she had previously glimpsed among the treasure cards for the 6th level.  Her wizard finally left the dungeon with 87,000 gp worth of treasure, including the diamond!

Sunday, November 3, 2019

The Town of Blackmoor

From the castle itself the small town of Blackmoor grew, then the surrounding countryside became filled with new holes to explore...
 Dave Arneson "The First Fantasy Campaign" (1977)
"Points of Interest in Black Moor" was published in Domesday Book #13 (July, 1972) together with a map of the town.

View of Branzoll Castle from the town square.  The view of Blackmoor Castle from Victory Square outside the Comeback Inn would be similar.  (Photograph from tripadvisor.)

Back in 2017, Havard shared this map on his blog (attributed to Domesday Book #13, but possibly from another source):

The ground plan of the castle is based on the Burg Brazoll model kit.

Within the town, the Silver Dragon Inn, the Comeback Inn, the Gallows, the Store, the Warehouse, the Church, and a Wharf are labeled.  Another forty smaller buildings are numbered.

There are three gates leading past the city wall:

The Swamp Gate to the east leads to a fork in the road, beside Elf Stump, in between three Pillars.  The road to the east leads to Bramwald, and the road to the north passes by Svenny's Freehold, then continues to the Wizard's Wood through Wolfshead Pass.

The South Gate leads to Tonisberg, while the Troll Gate to the west leads over a bridge to a fork in the road.  The road to the west also leads to Tonisberg, while the road to the northwest leads past Jenkin's Hill on the way to Glendower.

An island in the center of Blackmoor Bay is labeled Serpent Rock.  A small cave opening is visible, facing south.  A scale for the map is present in the upper right hand corner.

In December, 2016, another map was posted on the "Secrets of Blackmoor" Facebook page, along with some fascinating insights into pre-D&D Blackmoor adventures:

On this map, Jenkins Hill is labeled Vampire Hill, and Elf Stump is labeled Elf Home.  The buildings in the town are color-coded, red for David Megarry's thief McDuck's gang, and blue for Dan Nicholson's Merchant of Blackmoor.

In Playing at the World (2012) Jon Peterson states "...Duane Jenkins apparently wasted a wish to transform his character into a vampire - only to find that Arneson, exercising the latitude of the referee, exploited a loophole in his wording and turned him into a vampire rose bush."

Saturday, November 2, 2019

Blackmoor Castle

Blackmoor Castle was built in the third year of the reign of Robert I, King of all Geneva, as a defense against the Barbarian hordes that periodically sweep through this area over a period of six years.  On the hill that dominated the small village of Blackmoor, there are the ruins of several previous structures that were destroyed by the Barbarians.  The newer structure incorporates many of the underground galleries of the older structures as well as the main tower which has stood throughout the history of the area.
Excerpt from "The First Fantasy Campaign" (1977) by Dave Arneson
"Robert I, King of all Geneva" no doubt refers to Robert Kuntz, who was described as King Robert (Kuntz) I, of the Castle and Crusade Society, in Domesday Book #1.  The "Empire of Geneva" is mentioned in early campaign letters, (see this post).

In his original Blackmoor games, Arneson used a model castle to represent Blackmoor Castle.  The model kit, and the Italian castle it was based on, came to light in 2010 and can still be purchased on amazon.  You can tour the vicinity on Google Maps.

Branzoll Castle in Klausen, Italy (photograph from the tripadvisor website)

Arneson first mentioned the kit in an interview with Kobold Quarterly in 2009, although believed the model was of a castle in Sicily.  He possibly mixed up Chiusa (the Italian name of Klausen in South Tyrol) with Chiusa Sclafani in Sicily.

Dave's daughter, Malia, discovered some old maps of Blackmoor Castle in 2013.  The first floor was reserved for guests, the second for retainers, and the third for the royal family.  The tower portion contained two additional floors.

Photograph of Arneson's drawing of the entrance to Blackmoor Castle, part of the "Legends of Wargaming" exhibit at Gary Con XI (Gertie the dragon's tail is also captured, top left)

Arneson's original dungeon had six levels.  In the introduction to "The First Fantasy Campaign" (1977), he writes "Six levels was chosen since it allowed random placement with six-sided dice."  Dave Megarry's "Dungeon!" board game likewise features six levels.

By mid-1972, the players had so neglected the defense of the town in favor of dungeon exploration, that the castle fell to the invading forces of the Egg of Coot, bringing that phase of the campaign to a close.  In future adventures, the entrance to the dungeon was guarded by elves.

Corner of the Table (vol. 4, no. 6) in Nov/Dec 1972 marks the beginning of the Loch Gloomen adventures, around the time that Arneson and Megarry visited Lake Geneva to demonstrate Blackmoor and Dungeon! to Gygax.