The OD&D Game World: Fictional Mythos

The writings of H.P. Lovecraft, Robert E. Howard, and Michael Moorcock contributed significantly to the concept of an OD&D game world.  Fritz Leiber's "World of Newhon", while equally influential, wasn't detailed until AD&D's "Deities & Demigods" (1980).

The Lovecraftian Mythos:

See Zenopus Archives for a comprehensive survey of "The Cthulhu Mythos in D&D in the 1970s".

In their original "Known World" setting, Lawrence Schick and Tom Moldvay imagined that "in every land there would be hidden cults that worshiped Lovecraftian Elder Gods."

The Hyborian Age:

The Hyborian Age, Marvel Comics version.

Howard's Conan stories were set during a pre-cataclysmic Hyborian Age, circa 10,000 BC.  These were later adapted by Marvel Comics, becoming part of the Marvel Universe.

The OD&D game world might have likewise had a Hyborian Age.  Players desiring to adventure in Howard's fictional setting would need to travel into the distant past.

The Melniboné Story Line:

The initial treatment of "Law" and "Chaos" was inspired by Michael Moorcock’s treatment of good and evil in his "Elric" and other fantasy books written prior to 1970.

Gary Gygax, interview

The Elric stories were originally conceived by Moorcock to have taken place on an alternate earth, in an even more distant past.

Gary Gygax referred to the setting for the Battle of Brown Hills as "a mythical continent", predating that of the Great Kingdom.  I like to consider this scenario part of OD&D prehistory.

As the cosmic conflict between Law and Chaos faded in significance, so too might the conflict have represented a primordial one in the OD&D game world.

The OD&D Game World

In OD&D vol. 1: Men & Magic, a continental setting is mentioned:

The "common tongue" spoken throughout the "continent" is known by most humans.

In a letter to Alarums & Excursions, Gary Gygax stated that the Castle and Crusade Society map of The Great Kingdom was based on the continent of North America:

The game world is a parallel earth, but the continents are somewhat different.  Most of our campaign activity takes place on what corresponds to North America, on the eastern half of the continent.  The "Blackmoor" lands lie far up on the northeast coast.  "Greyhawk" is in the central portion.  There are a few other independently run campaigns located on this map.  There are also some other dungeons related to the "Greyhawk" campaign located at some distance from the free city of Greyhawk.   Players in our campaign may freely play in "Blackmoor", but to get there they must adventure cross country.  With one or two other campaigns, we do not allow any cross-campaign play other than this, for these is too great a disparity of DMing.  The territory within 500 or so miles of our main dungeon is mapped out at 5 miles to the hex.  Territory within 50 miles of Greyhawk city is mapped more closely, and monster locations are indicated.  The entire world is mapped out in rough form, with notes regarding typical encounters in given areas as well as particular special places, for hardy souls who wish to go forth to seek their fortunes.

Gary Gygax, Alarums & Excursions #15 (October, 1976)

It's intriguing to note that an OD&D game world existed in rough draft.  Gygax later provided additional details in answer to a query regarding this pre-1978 campaign setting:

The planet was much like our earth.  Think of the world of Aerth as was presented for the MYTHUS FRPG.

The city of Greyhawk was located on the lakes in about the position that Chicago is, and Dyvers was north at the Milwaukee location.  The general culture was pseudo medieval European.  Some of the kingdoms shown on the WoG map were around the adventure-central area, the City of Greyhawk.

More details aren't really possible, as the sketch maps I used are long gone.

Q&A with Gary Gygax, En World, Apr 14, 2003

Gods, Demi-Gods & Heroes is often dismissed as nothing more than a high level "Monster Manual", but actually provides a great deal of material for such an OD&D campaign setting:

The mythos described in Gods, Demi-Gods & Heroes, as well in several articles published in The Dragon, provide a rich template for an OD&D game world, based upon several cultures in our own world.

Three characters in the original Greyhawk campaign were famously transported to "China" as described in an article by Gygax, published in Dragon #295 (May, 2002).

The entry for rakshasas in The Strategic Review #5 begins "Known first in India, these evil spirits encased in flesh are spreading".

In this vein, creatures drawn from Greek mythology, such as medusas and minotaurs, might have originated in "Greece" (and therefore speak Greek, as opposed to their own languages).

With respect to character classes, monks could be from "Tibet" (Gygax stated that he "envisaged them mainly as wanderers from afar"), samurai and ninja from "Japan", etc.

World of Greyhawk:

While Gygax ran his original Greyhawk campaign in a shared OD&D game world, in which Dave Arneson's Blackmoor campaign and Rob Kuntz's El Raja Key also existed, he later went on to create the separate "World of Greyhawk" setting for the AD&D game.

The Epic of Aerth:

Interestingly, we get the best glimpse into how the OD&D game world might have been envisioned from Gygax's "The Epic of Aerth" campaign setting, for the short-lived "Dangerous Journeys" RPG.

See the following links for maps of the World of Aerth, including the various continents.  Additional resources for Aerth include "Necropolis and the Land of Ægypt", the unpublished "City of Ascalon", and a trilogy of novels, written by Gygax.

Gods, Demi-Gods & Heroes: Other Mythos

In addition to the eight mythologies covered in Gods, Demi-Gods, and Heroes, several additional mythos were covered in The Dragon between February, 1978 and September, 1979.  These included the Cthulhu mythos, as well as seven other mythologies, by Jerome Arkenberg,

The Lovecraftian Mythos in Dungeons & Dragons

The Dragon #12 (February, 1978)

The manuscript for this article was written by J. Eric Holmes, with a few editorial changes made by Robert Kuntz, as discussed at Zenopus Archives here and here.

The Lovecraftian Gods, the Great Old Ones, and the Necronomicon, are described.  There are additional entries for Inhuman and Partly Human Races of the Cthulhu Mythos.

See also "The Cthulhu Mythos Revisited", a letter submitted by Gerald Guinn, in The Dragon #14, and "A Rebuttal to "The Cthulhu Mythos Revisited", by Holmes, in The Dragon #16.

The Persian Mythos

The Dragon #12 (February, 1978)

The ancient Persian religion, Zoroastrianism, is a dualist system.  This means that the Persian Gods are either Good (Lawful), or Evil (Chaotic).  Ahura Mazda, the Archangels, and the Yazatas are opposed to Ahriman and the Archdemons, who try to destroy Ahura Mazda's creations.

The Forces of Good (including Ahura Mazda or Ohrmazd, the Archangels, the Yazatas) and some heroes, as well as the Forces of Evil (including Ahriman or Angra Mainyu, the Archdemons, and lesser Demons) are described.

The Japanese Mythos

The Dragon #13 (April, 1978)

Japanese mythology is a mixture of Buddhism and Shinto.  The main concern of Shinto is with Amaterasu, the Sun Goddess, and her relations and descendants.  The beliefs of Shinto also includes the belief that everything (mineral, animal, and vegetable) has its own kami or spirit.  When Buddhism was introduced to Japan in the late 6th Century A.D., Shinto gods and goddesses, to a certain degree, became integrated with the Buddhist pantheon, and vice versa.

Bishamon trampling a demon, illustration by David Sutherland, from The Dragon #13.

The gods and goddesses of Japanese mythology, as well as a list of special treasures, are included.  Ogre magi were previously included as D&D monsters in Greyhawk.

Oni, or "Japanese Ogres", were inspired by General Raiko and the Ogres of O-E-Yama, a beautifully illustrated children's book translated into English from Japanese, according to Gygax.

A samurai character class by Mike Childers and Jeff Kay was published in The Dragon #3, as was a ninja character class by Sheldon Price in The Dragon #16 (updated in The Dragon #30).

Near-Eastern Mythos

The Dragon #16 (July, 1978)

The mythologies of Sumeria, Babylonia, and Canaan are quite similar to each other.  Usually, only the names of the deities are different (though there are slight differences, due to local needs).  This is attributable to the fact that these mythologies all stem from that of the Sumerians (though local gods were added to it).

Scorpion Man, illustration by David Sutherland, from The Dragon #16

Descriptions are given for the various gods, heroes, monsters, and artifacts of ancient Mesopotamia, with designations provided for Sumerian, Babylonian, or Canaanite origins.

The Mythos of Australia

The Dragon #19 (October, 1978)

The mythos of Australia is not that of the white settlers, but of the Australian Aborigines.  These were primitive semi-nomadic hunters and foragers living in a hostile, arid environment.  There were many aboriginal tribes, widely separated over the continent of Australia.  Thus though they had many Gods in common, they also had many others that were peculiar to a certain tribe or area.

Sky-Beings (gigantic, human-shaped beings), and other creatures (including the Rainbow Snake, the Wondjina, and the Mimi) are described.

The Mythos of Polynesia

The Dragon #20 (November, 1978)

Polynesia comprises those islands in the Pacific Ocean that stretch from the Hawaiian Islands in the North, to New Zealand in the South, and to Easter Island in the East.  In this vast area of the Pacific, the Islanders have a distinct, but related culture, language, and mythology, much as those Scandinavians do.  Thus their Gods, Goddesses, and Heroes have basically the same traits and characteristics, though they are often known by different names.

The various gods and goddesses of Polynesian mythology are described, in addition to "the Great Octopus", heroes, monsters, and artifacts.

Holmes, who spent part of his childhood in Hawaii, created the were-shark, and makes reference to "were-sharks in Polynesia" in the Basic Rulebook (1977).

The Mythos of Africa

The Dragon #27 (July, 1979)

The mythology of that part of Africa which lies south of the Sahara was not written down until recently, and is still not complete.  but the myths of the several tribes were preserved in oral tradition and African art.  There are many, many tribes in that part of Africa, and each have their own myths and legends.  But yer many of these myths are similar in theme and events, even if the names are different.

Several gods, creatures, and heroes are described, including an artifact "The Golden Stool of the Ashanti".

The Mythos of Oceania

The Dragon #29 (September, 1979)

Oceania, in this regard, consists of two diverse groups of islands - Micronesia and Melanesia.  The former consists of the small Pacific islands and atolls that comprise the Palau, Caroline, Marshall, Gilbert, and Mariana Islands.  the latter consists of such large Pacific islands such as New Guinea, New Caledonia, the Fiji, New Hebrides, Solomon, and Santa Cruz Islands, and the Bismarck Archipelago.

"The mythos of Micronesia emphasizes heroes, and is not very concerned with gods or goddesses."  The gods and heroes, as well as creatures, are described.

"This mythos, in contrast to that of Micronesia, emphasizes gods and their importance to Mankind."  The Kasa Sona, heroes, and creatures are described.

When "Deities and Demigods" was published for AD&D in 1980, the Babylonian, Japanese, and Sumerian mythos were included.  I was surprised to see that Jerome Arkenberg wasn't listed in the acknowledgements.

Someday, I would like to see a fan-made "God, Demi-Gods & Heroes: Volume II".  There was as much material published in The Dragon as presented in the original supplement, and J. Eric Holmes and Jerome Arkenberg could be credited as the co-authors.

Gods, Demi-Gods & Heroes

OD&D Supplement IV: Gods, Demi-Gods & Heroes was billed as "the last D&D supplement" in The Dragon #2.  It was co-authored by Robert Kuntz and James Ward, as discussed in this interview with Ward on the "Save or Die!" podcast.  The foreward is by Tim Kask.

D&D Supplement IV: Gods, Demi-Gods & Heroes (July, 1976) by Robert Kuntz and James Ward.  Cover illustration by David Sutherland, depicting Horus "the Avenger" (wearing the pschent, a red and white crown, left) facing his half-brother Anubis "Guardian of the Dead" (right).

The various gods and demi-gods are ascribed psionic abilities of increasing strength (class 1-5) or are listed as immune to psionics (class 6), and their ability scores, unless otherwise stated, are considered to be 20 across the board.

In his article "D&D is only as good as the DM" published in The Strategic Review #7, Gary Gygax implies an upper limit of 14th level for player characters.  The magic and fighting abilities of the various deities appear to reflect this.

Egyptian Mythology:

The ancient Egyptians had a culture lasting over 3,000 years.  It is only natural that their faith would undergo a change.  Their Gods aged with Ra starting as the ruler and growing senile and Osiris taking over after being killed by Set.  The pantheon presented is one with Ra in prominence only because there are more Gods in this early group.

Ward expresses his admiration for Egyptian mythology in the above-mentioned interview on the "Save or Die!" podcast.

"Minions of Set" (10th level fighters able to transform into giant snakes) are described.  New monsters include the sphynx, fire snakes, winged serpents, and phoenix.  A magical weapon, the "life scepter" usable by the Gods (mainly Thoth), is also described.

Alan Lucien's Tomb of Ra-Hotep, the inspiration for Gary Gygax's "Tomb of Horrors" is situated in an Egyptian-type setting.

Gods of India:

Several Hindu deities are described, possibly inspired by Roger Zelazny's Hugo award-winning science fantasy novel Lord of Light (1968).

Modified statistics are given for rakshasas (originally appearing in The Strategic Review #5) and nagas (originally appearing in The Strategic Review #3).

New monsters include maruts (wind spirits), yakshas ("weaker demons of India"), ribhus (as per D&D elves), and ogres (as per D&D, but can polymorph themselves).

Steve Marsh's OD&D mystic is well suited to an Indian-type setting.

Greek Mythology:

Polyphemus the Cyclops at the opening of his cave, staff in one hand and pipes in the other.  Three sea nymphs and a dolphin are in the background.  Anonymous woodcut in The Strand Magazine, July- Dec 1892, page 204 and also in "1000 Quaint Cuts", page 47.  Mary Evans Picture Library

Several D&D monsters were drawn from Greek mythology, including chimeras (the illustration in Blackmoor was likely based on an Etruscan sculpture), hydras, medusas, minotaurs, and titans.

Statistics are given for Cerberus and the Hundred-Handed One.  New monsters include cyclopes (one-eyed giants), and satyrs.

The Celtic Mythos:

The Celtic mythology is by no means confined to the English Isles.  The Gods are all in human form as opposed to some of the other pantheons mentioned.  They all have spheres of influence given for each God.  These spheres are areas of control for the Gods and any manipulation of them by humans or other life forms causes the Gods to take an interest.

Several gods from Celtic mythology are described.  New magic items include the "torc of the gods" (allowing the holder to shapechange at will) and a weapon of war, the "tathlum".

In his article on bards in The Strategic Review #6, Doug Schwegman states:

The Celts, especially in Britain, had a much more organized structure in which the post of Bards as official historians fell somewhere between the Gwelfili or public recorders and the Druids who were the judges as well as spiritual leaders.  In the Celtic system Bards were trained by the Druids for a period of almost twenty years before they assumed their duties, among which was to follow the heroes into battle to provide an accurate account of their deeds, as well as to act as trusted intermediaries to settle hostilities among opposing tribes.

Schwegman also states "Bards and Druids are closely connected and since they both belong to the same sect each must aid the other if they are in need."

Bob Blake's Gen Con IX dungeons take place in a world "roughly similar to Celtic mythos", a setting revisited in Blake's later "Prophecy of Brie" cycle.

The Norse Gods:

Illustration of Odin from "Old Norse Stories" page 119, by Sarah Powers Bradish (1900).  The entire text, complete with illustrations, is downloadable at archive.org

Gods, Demi-Gods & Heroes includes an extensive section on Norse mythology  Ward mentions The Mighty Thor as an influence, in his interview on "Save or Die!"

Statistics are given for Garm, the Fenris Wolf, and the Midgard Serpent.  New monsters include nissies (brownies), neck, and fossergrims.

Paul Karlsson Johnstone discusses berserkers in his excellent article "Origins of the Norse Pantheon" in The Dragon #29 (September, 1979)

The Finnish Gods and Heroes:

The action here takes place in Lapland and its environs, including Pohjola "a dark, dismal country north of Lapland."  Unlike other mythologies, the heroes are the powerful ones here.  If you have read the Malevella you will know what I mean.

The section on Finnish mythology describes the Finnish heroes, their powers and weapons, as well as the Finnish gods, monsters, magical items, and new spells.

Gygax's famous character, Mordenkinen, was inspired by Finnish myth:

The background I created for Mordenkainen was Finnish-like in nature, and his master was a chap called Old Waino...I picked the name because one Vainomoinen was sometimes referred to as "Old Waino."  I really was captivated with Finnish myth after seeing a B&W movie done by the Russians, I think, about him, Leminkainen, and Ilmarinen adventuring to Pojola and entering Louhi's fortress, then reading "The Green Magician" by de Camp and Pratt as well as the Kalevala.

Gary Gygax, En World, June 13, 2006

The film Gygax refers to was probably "Sampo", edited and released in the U.S. as "The Day the Earth Froze".  The Finnish version was apparently restored and released on DVD in 2014.

"The Green Magician" by L. Sprague de Camp and Fletcher Pratt, one of their Harold Shea stories, was reprinted in The Dragon #15 and #16 (1978).

Robert E. Howard's Hyborea:

Conan's world is very real in that Robert E. Howard went to great lengths to limit his magic and sorcery to firm up the believability of his stories.  The Gods of his world are of many types and go from one extreme to the next in working, or leaving  alone, mankind.

Stats for Conan are included (F15/T9; Str 18/100%, Int 16, Wis 10, Con 17, Dex 18, Cha 15).  Gygax later provided AD&D stats, in The Dragon #36.

Set is the same as in the Egyptian section.  Various characters, monsters, and magical items from the Conan stories are described.

The Kraken makes reference to the novel "Dwellers in the Mirage" by A. Merritt (1932).

Elric and the Melnibone Story Line:

Stats for Elric and Stormbringer are included, in addition to other characters, monsters, and magical items from the Melnibone stories.

Neither the Hyborean nor Melnibonean sections were included in Wizards of the Coast's reprint of Gods, Demi-Gods & Heroes (2013).

Mexican and Central American Indian Mythology:

Due to the lack of space in this booklet we, the authors, are only able to present parts of this mythology.  What is listed below will be mainly the gods & let it be noted that information on these divinities is scarce.

A short section touching on Aztec mythology.  Quetzacoatl (Kulkulkan "in Incan") is described as the feathered Serpent-God of Mayan religion.

Stone carving of The Feathered Serpent, Temple of Quetzalcoatl, Teotihuacan.  Illustration by Lynn Harpold, from The Dragon #2 (August, 1976).

See also "The Feathered Serpent" by Lynn Harpold, in The Dragon #2.

Harold Johnson and Jeff R Leason's adventure "Lost Tamoachan: The Hidden Shrine of Lubaatum" (Origins, 1979) was heavily influenced by Mayan and Aztec/Toltec mythology and society.

Eastern Mythos:

The mythology of the Far East is varied and colorful.  In dealing with it, the concepts of Yin and Yang must be defined.  These are the Chinese equivalents of bad and good.  These opposites are almost beings in themselves and move all Gods and creatures in a war for supremacy.  In using eastern Gods one should always think of them as not lawful or chaotic, but having good Yang or bad Yin.

The final section covers Chinese mythology.  Descriptions are provided for various gods and demi-gods, in addition to spirits and demons (stats for rakshasas are used for the latter).

Several magic devices are described, including a Giant Black Pearl (negates all wind and earth turbulence in a 1 mile radius), which brings to mind the great black pearl "of the gods" mentioned in module X1 "The Isle of Dread".

See also "Chinese Dragons" (The Dragon #24) and "Chinese Undead" (The Dragon #26) by David Sweet.

Origins II: Expedition to the Barrier Peaks

Gary Gygax, with help from Robert Kuntz, prepared "Expedition to the Barrier Peaks" as the D&D tournament dungeon for Origins II, held July 23-25, 1976 at Johns Hopkins University, Baltimore MD.  Revised for AD&D, the adventure was published as S3: Expedition to the Barrier Peaks (1980).

Advertisement for Origins II, from The Strategic Review #7 (April, 1976).

On the front page of the AD&D module, Gygax stated:

This module was the official "Advanced Dungeons & Dragons"* Tournament scenario at Origins II.  The author wishes to express his thanks to Mr. Robert Kuntz who contributed substantial ideas for the various encounters herein.

*Technically, Advanced D&D had likely not even yet been conceived in July, 1976, so the above needs to be appreciated in the context of the legal situation involving Dave Arneson in 1980.

In the preface for S3: Expedition to the Barrier Peaks, Gygax wrote:

This module was begun early in 1976 when TSR was contemplating publication of a science fantasy role playing game.  Jim Ward had already shown us some rough notes on METAMORPHOSIS ALPHA; I thought it would be a splendid idea to introduce Jim’s game at Origins II, and introduce the concept to D&D players by means of the tournament scenario.  I laid out the tournament from old “Greyhawk Castle” campaign material involving a spaceship, and Rob Kuntz helped me to populate the ruined vessel.  Both this scenario and METAMORPHOSIS ALPHA proved successful, but while the latter has been continually available since mid-1976, only a few copies of the tournament dungeon used for Origins II have been around.

Gary Gygax, S3: Expedition to the Barrier Peaks, 1980

The level of old "Greyhawk Castle" involving a spaceship might be in reference to Kuntz's "Machine Level", used as the D&D demo at Gen Con VII (1974).  James Ward described the technological level in his article "Boredom and the Average D&D Dungeon", from Dragon #17 (August 1978):

The Future or Machine Age: While some steady readers might think that I harp on this topic too much, the first time I came in contact with a level of this type was in the “mighty” castle of Greyhawk; run by Gary Gygax and Rob Kuntz.  Imagine conveyor belts that force players to travel in one direction or another, a cellophane machine that wraps you up no matter how big or small you are and puts you in a Vol. III No. 3 holding area for as long as it takes to rip yourself out, how about a die press that shapes anything in its path into a bottle top (Boy, can that hurt!), or a row of blades that cut in a pattern on the belt with a 25% chance that any given blade will cut you?  Try a slot machine that takes only large sums of gold and with the flip of the handle takes a random magic item from the party, and how about a lever that turns on something way off in another part of the level (like a robot or level clean up machine) that you can’t know about until you travel to that part of the level?  The treasures of this level could easily be more fun than the level: imagine bottle tops made out of mithril on wine bottles; how about guns and pistols that work; a set of chain mail made out of a super hard and light alloy that acts like plus 5 armor and shows no magical traits; how about a huge pile of gold dust in a large plastic bubble that isn’t small enough to get out the door and can’t be cut by anything less than a plus 5 sword?

James Ward, Dragon #17 (August, 1978)

Ward had already contributed an article "Magic and Science: Are They Compatible in D&D?" published in The Dragon #1 (June, 1976) in preparation for the D&D tournament at Origins II and the release of Metamorphosis Alpha (July, 1976).

It's been suggested that Gygax may have gotten the idea for "Expedition to the Barrier Peaks" from the novel "The High Crusade" (1960) by Poul Anderson, in which an alien spaceship lands in medieval England, (discussed on the Appendix N Book Club podcast in October, 2018.)

Cover to the 1st edition of "The High Crusade" (1960) by Poul Anderson.

It should be noted that Dave Arneson likewise mixed fantasy and science fiction elements in his Blackmoor campaign, most notably in The Temple of the Frog and The City of the Gods, and that Arneson famously ran an adventure for Gygax and Kuntz in the City of the Gods in early 1976.

The City of the Gods is revealed to be a crashed spaceship in the BECMI module DA3: City of the Gods (1987), co-written by Arneson and David J. Ritchie, although I'm not certain whether Arneson's original City of the Gods was intended to represent a marooned spacecraft.

Expedition to the Barrier Peaks:

Copies of the tournament scenario from Origins II are exceedingly rare.  Kuntz blogged about a copy sold on ebay in 2010.  Allan Grohe very kindly posted some photographs of a personal copy on his blog in October, 2018, from which it's possible to read the tournament background:

The Duchy of Geoff has recently been plagued by a rash of weird and terrible monsters of unusual sort.  The area to the west, particularly the foothills of the Barrier Peaks which separates the Duchy from the Sea of Dust, has long been renowned for the generation of the most fearsome beasts, and it has been shunned accordingly by all save a handful of hardy souls with exceptional abilities and sufficient wealth to build stout strongholds to ward off the attacks precipitated by these beasts.  Within the last few months, however, a walled town not far distant from the area, as well as four castles, were destroyed by mysterious attacks.  The local barons and lords who remain have sent in several decomposed bodies of some of the creatures assumed to have been part of these attacks, but the bodies were in such state that nothing could be learned.  The urgent plea for aid which accompanied these remains could not be ignored.  The Duke acted immediately, selecting several of his doughtiest warriors and called upon other powers in the realm to send their minions also.  Thus, the Society of the Mages, the Fellowship of the Blinding Light, the Thieves' Guild, and the Lord of Elves in the region have also selected brave adventurers and equipped them accordingly to accompany the expedition. A total of 15 characters assembled.

Expedition to the Barrier Peaks, 1976

This background information is interesting in that, as with The Tomb of Horrors from Origins I, it refers to locations within the original OD&D setting, based on the map of the Great Kingdom:

Map of the Great Kingdom from Domesday Book #9 (1971) with location of the Barrier Peaks, separating "the Duchy (of Geoff) from the Sea of Dust."

There were several changes made to the background information, when the adventure was revised for publication as module S3:

Duchy of Geoff → Grand Duchy of Geoff
Sea of Dust → Dry Steppes
Society of the Mages → Society of the Magivestre
Thieves' Guild → Magsmen's Brotherhood
Lord of Elves → High Lord of Elvendom (at Hocholve)

By changing the Sea of Dust to the Dry Steppes, the location of the Barrier Peaks shifted from the southwest border of the Duchy of Geoff to the northwest border of the Grand Duchy of Geoff.

The Fellowship of the Blinding Light is also mentioned.  In Outdoor Geomorphs Set One: Walled City, published the following year, an example for city locales is given: "Just up Pennyless Walk is the Almshouse of the Brothers of the Blinding Light."

The Greyhawk deity Pholtus of the Blinding Light (Light, Resolution, Law, Order, Inflexibility, Sun, Moon) was described in Dragon #68 (December, 1982):

It is said the regularity of sunrise and sunset, the cycles of the moon, are as fixed as the resolve of Pholtus to show all creatures the One True Way, a strict path which allows no deviation but gives absolute assurance of rightness.  Some followers of the Blinding Light actually claim it is their deity, Pholtus, who ordered the rigid progression of the sun and moon and maintains them in his regimen.  Such claims are not regarded as doctrine.

As a Mystara fan, I see parallels between Pholtus and the Mystaran immortal Ixion.

Suggested levels:

The AD&D module is billed as "An adventure for character levels 8-12" although within suggests a party size of "10-15 characters with most having levels between 5th and 10th".

I wonder if this is a holdover from the tournament version, since the list of 15 pregenerated characters possess levels ranging from 4-12, with an average level of 7.6, and are limited to races and classes from OD&D + Greyhawk.

The suggested levels for the AD&D version appears to limit the adventure to high-level characters, but judging from the pregens, lower level characters (levels 4-10) may be used.

Using "Expedition to the Barrier Peaks" in your OD&D campaign:

The hook for this adventure is an easy sell for lawful-type, heroic parties.  While deadly, it's not as unforgiving as the Tomb of Horrors.

The science fiction element can serve to spice up a campaign in which the PCs are eager to try something new, taking the party into unfamiliar territory.

Gygax even transported a group onto the Starship Warden, as described in his article "Faceless Men & Clockwork Monsters", published in The Dragon #17 (August, 1978).

Greyhawk Castle: Expanded Version

The first Greyhawk Castle was designed by Gary Gygax in late 1972 and 1973, while playtesting the original D&D rules.  El Raja Key was created by Robert Kuntz, soon afterwards.  Gygax and Kuntz subsequently collaborated to revise and expand the original Greyhawk Castle, in 1974.

The adventures taking place in the dungeons beneath the first castle, refereed by Gygax, as well as in the megadungeon beneath the expanded castle, co-refereed by Gygax and Kuntz, attained legendary status.  To date, neither version of the castle has ever been published.

In January, 2019, we learned the following:

The manuscript for Gary's, unpublished, original home campaign is still extant!  Indeed, I have unearthed the original castle manuscript of 22 levels.  Also, the larger, expanded castle of 62 levels is also intact and well secured by Gary's widow, Gail Gygax.  Additionally, there are over a dozen alternate levels that were used to change out levels depending on who was playing.  In total nearly 100 levels of the castle exist with some 300 pages of keys.

Paul Stormberg, r/rpg, here

The original castle was 13 levels deep, with side-levels branching from these.  Gygax and Kuntz incorporated several of the levels from Kuntz's El Raja Key in constructing the expanded castle, comprised of a central core with four main branches.

Museum of the Gods, from Greyhawk Castle (downloaded from Gygax Games website). See this thread at Knights & Knaves Alehouse for discussion.

Of the 62 levels in the expanded castle, 41 were designed by Gygax and 21 were designed by Kuntz (6 were a joint effort).  Kuntz has requested that his original levels and their keys be returned to him (you can read about it on his Facebook page, here).

For those of you wondering what Kuntz's levels for the expanded version of Greyhawk Castle look like, you can access the maps through the El Raja Key Archive, released in 2016.  For a sense of what this means for the typical OSR gamer, check out this video by the Jaded Fanboy.

While I'm hopeful that we'll eventually see the manuscripts for both versions of Greyhawk Castle published, it's at least possible to summarize the various details on the layout of the expanded castle into a core dungeon with extensions to the north, south, east, and west.

Upper Works:

Using a couple of sheets of 17" x 22" graph paper, I drafted a complete, mostly undamaged castle above ground.  It had multiple levels, and a lot of encounters, the higher up, the more dangerous.  Then, using the same sort of paper I drew a new first level that could accommodate both bands of fledgling adventurers and the initiated.  Four separate descent areas were created with designation by the cardinal directions.  Each had multiple flights of stairways leading lower, some ending several levels farther down.  Three were "guarded" by dungeon denizens - elves, dwarves, a very large and strong ogre.  One descent area only, that most difficult to find, was deserted and free of "charge" by some guardian.  The vast majority of the space, however, was filled with passages, chambers and rooms...

As was indicated in the Gord short story, "Heart of Darkness", Castle Greyhawk indeed had a fifth descent area.  In the very center of the first level, where most explorers entered via the circular stone steps there, was a hard-to-discover secret entrance to the continuation of that spiral stairway.  It went down all the way to the ninth level, with some side exits along the route accessing some intermediate levels not generally accessible save from this shaft...

The side entrances to the second and lower dungeon levels were basically insular.  That is, each led to a series of seven lower levels that were distinct, so that there was North #2 through #8, East #2 through #8, South #2 through #8, and West #2 through #8...  These sets of levels had few inter-connections, save at the very bottom, where each eighth level had a connection down to the ninth, central, level.

 Gary Gygax,"Founding Greyhawk", Dragon Annual #2, 1997

Core Levels 2-9:

Core Level 2 - "Invisible Maze" Level (ERK Level 2) according to ERK Archive

Core Level 3 - "Gem Room and Crypts" Level (ERK Level 4)

Core Level 5 - "Sealed Tomb" Level (ERK Level 5) according to ERK Archive

Core Level 6 - "Black Pudding Doorkeeper" Level (ERK Level 6)

Core Level 7 - "Multi-Layered" Level/Tsojconth Level (ERK Level 10)

[The Tsojconth Level] was originally part of Castle El Raja Key and corresponds with Castle El Raja Key Level 10.  This is Rob's original map but his key still resides with Gary Gygax's copy of the Expanded Greyhawk Castle.  Gary liked the design so much that he borrowed the idea and it became the Greater Caverns for the WinterCon V tournament module, the Lost Caverns of Tsojconth in 1976.  Rob's original map, shown here, was edited by Rob and Gary for use in the Expanded Greyhawk Castle as Core Level 7...

from the El Raja Key Archive, 2016

Core Level 7.5 - Black Reservoir

This level was featured in Gygax's short story "The Expedition Into the Black Reservoir" published in El Conquistador, vol. 1, no. 12, August 1974)

North Levels:

North Level 8 - The Lake (map and key by Gygax, based on Kuntz's original design)

East Levels:

East Level 3 - "Split Garden/Giant's Pool Hall" Level

Possible location of Kuntz's Garden of the Plantmaster

East Level 6 - "Living Room" Level (see The Living Room (Pied Piper Publishing, 2007)

East Level 8 - "Machine" Level (discussed here) used as D&D demo at Gen Con VII (1974)

South Levels:

South Level 8 - Repeating Hex Rooms (drawn by a classmate of Ernie Gygax)

GC S8/X1 Alice in Wonderland → EX1 ("Extraplanar") Dungeonland (TSR, 1983)

GC S8/X2 Through the Looking Glass → EX2 The Land Beyond the Magic Mirror (TSR, 1983)

South Level 9 - "Horsing Around" (or "Greek Mythos", a split level)

West Levels:

West Level 3 - "Invisible Maze" Level (according to Stormberg)

West Level 5 - "Gallery" Level

West Level 7 - "Barracks" Level (ERK Level 7)

Core Levels 10-20:

From nine on, the levels of Castle Greyhawk progressed straight down for another dozen or so tiers...  Not surprisingly, a number of these levels also had magical transportation places that sent PCs off to distant lands, other dimensions, strange worlds, or different times.

Gary Gygax,"Founding Greyhawk", Dragon Annual #2, 1997

Core Level 10 - "The Great Stone Face Enigma" Level (Kuntz redrew Gygax's original map)

Core Level 11 - "Entrance to Oz" (Emerald City) Level

Core Level 12 - "Boreal" (Ice) Level

Core Level 12 - "Valhalla" (a sub-level)

Core Level 13 - "Entrance to Asgard, Melnibone, and Dying Earth" (Fire) Level

Core Level 14 - "Orb, Scepter, and Crown" Level

Core Level 16 - "Entrance to Bottle City" Level (keyed by Kuntz and Gygax)

RJK-1 Bottle City (Pied Piper Publishing, 2007; Black Blade, 2014)

Core Level 18 - "Gargoyle" Level (keyed by Kuntz)

Core Level 20 - "Dragon" Level (map by Kuntz and Gygax)

Other levels include the Skull Island/King Kong extraplanar level → WG6 Isle of the Ape (TSR,1986), and "The Teeth of Barkash Nour" (discussed here):

In the bottom-most level of the Castle Greyhawk dungeons lies a massive gate of horn, beyond which is a small dimension.  Within lie weird environments including a savannah of mobile plants that attack interlopers, a great "Egyptian" tomb, a desert of golden dust where north equals south and south north, a frozen wasteland and a huge lake where a large Slimey Horror possessing huge claws and the ability to reduce the unlucky to yellowish clay if the thing's mucous is breathed on them when they are in the water.  It is also the demesne of a mighty storm giant.  Fabulous treasures can be won in each of these lands, but the mightiest of them are the fabled Teeth of the Barkash Nour.  Those passing through the Gate of Horn at the very roots of the dungeon of Castle Greyhawk have but twenty four passing hours to locate the teeth and retrieve them all, else be expelled from the weird plane, never permitted to enter again...

The Dungeon Delver, from a comment on Zenopus Archives, March 2015

For more on the expanded castle, readers are advised to check out grodog's "The Many Levels of Castle Greyhawk", here.