As it is natural and proper, all other worlds revolve around our own planet Oerth, from the last rock to the vast burning sun itself. Little is known of these worlds, though a set of magnifying lenses or magical cusps reveals their curious shapes and colors, and their motions across the sky are all well charted. As any rational individual knows, these wandering stars influence the lives of all beings on Oerth, and their positions against the vault of night give hints to learned astrologers about events yet to come, revealing secrets fearful and sublime.
Oerth rotates on its axis once every 24 hours. The sun travels the sky from east to west, revolving clockwise in its orbit around Oerth to make a full circuit of the heavens every 364 days, following a fixed path through the Twelve Layers of the Zodiac. Though the Zodiac of the night sky also passes the Great Moon of Oerth, known as Luna, and the lesser moon, Clelene, also known as the Handmaiden. Ghost-white Luna waxing and wanes in a fixed cycle of 28 days, reaching fullness 13 times a year. Aquamarine Celene passes through its phases more slowly, taking 91 days for a full cycle and reaching fullness only 4 times a year. These natural rhythms are reflected in the calendar used by civilized inhabitants of our land.
It is known that with both Luna and Celene are either full or new, and the wandering stars have made them selves achieve positions of power within the zodiac, events of great portent are likely to occur in our world. The fate of civilization may be in the balance, and the involvement of great magic is also certain. The appearance of a falling star has further significance, and a great pale comet or bright exploding star hovering in the darkness is a harbinger of cataclysm.
-- Agath of Thrunch
The original inhabitants of the Flanaess were the Flan tribesmen, hardy and tough nomads whose small, scattered groups made no major civilizing efforts. Some thousand years passed, their lands were increasingly invaded by two groups of attackers: the Suel and the Oeridian.
The Suel fled from internal strife within their own lands and the great Baklunish-Suloise Wars. They moved northeast across what is now the Sea of Dust, across the formidable Hellfurnaces and Crystalmist Mountains, and spread widely across the land before them.
The Oeridians began their migrations north for similar reasons, fleeing the same war. Both Bakluni and Suel forces employed mercenaries, bandits, and any humanoids they could hire to swell their armies. Their undisciplined rabble were often only too happy to desert and attack the Oeridians, also forcing them eastward.
The Oeridian were fierce invaders. They drove everyone else, FIan and Suel, before them. Of all the invaders, they were most successful in establishing settled lands wherever they went, and any threat the Suel might have offered to their dominance was soon illuminated. Suel mages brought down the terrible Invoked Devastation on the hapless Bakluni in the north, but the last act of the Bakluni archmages was a fitting reply. The storm of the Rain of Colorless Fire reduced the Suel lands to choking dust and ash. There were a few Suel or Bakluni left to immigrate after that. The Oeridians had the upper hand.
The fierce Oeridian tribes hardly had matters all their own way. For two centuries, they fought the Suel and the fragmented humanoids for possession of the central lands of the Flanaess. The Oeridians incurred the enmity of the Flannae and demi-humans of the lands as well. The arrogant Oeridian might have been overcome by the mix of force, but for one thing: the Suel were far more unpleasant than the Oeridians were aggressive. The Suel invaders lied, cheated, stole, enslaved, pillaged, and killed out of hand. Over time, the Flannae and demi-humans allied with the Oeridians to drive the Suel to ever more distant fringes of the Flanaess: into the northeastern Barbarian land and into the southern jungles of Amedio and Hepmonaland.
On the main continental landmass, the Suel retained a foothold only in the southwest and in The lands that would eventually belong to the Scarlet Brotherhood. Approximately 700 years passed, the strongest Oeridian tribe -- the Aerdi -- settled the rich arable lands east of the great Nyr Dyv and there founded the Kingdom of Aerdy, which eventually became the Great Kingdom. The Kingdom grew for well over a century, until it stretched from the Sunndi swamplands to the south, to the southwestern edge of the Griff Mountains to the north; while from the island now held by the Sea Baron to the east (where the Aerdi mixed with Flan blood), the Great Kingdom stretched westward as far as the borders of modern-day Perrenland. When the Overking of this mighty empire declared universal peace on his ceremonial crowning in Rauxes, he must have thought his writ, and that of his descendants would extend across those many lands forever. The Great Kingdom survived some 250 years before it began to lose lands in the west.
The Overking could not reestablish control over his distant former dominions. The break-up of the Great Kingdom, which would take over three centuries to complete and would end in madness and terror, had begun. The decisive phase in the break-up of this mighty empire can be dated precisely to 356 CY. ln this year, the ruling Aerdi dynasty, the House of Rax, was sundered by an internal feud.
Elsewhere, the Free City of Greyhawk, already in existence for centuries as a trading town, entered its arguably most glorious (and certainly most infamous) phase of development under the mad Archmage Zagig Yragerne, who began the building of Castle Greyhawk in 375 CY. It seemed a strange folly at the time. Yet two centuries later, the changes in the city of Greyhawk and those back within the Great Kingdom would be pivotal in the future history of all the Flanaess.
Paradoxically, the disintegration of the Great Kingdom paused a while, despite a wretched change at its very crown. The House of Rax became decadent, self-absorbed weak, and ineffectual. Petty nobles began to scheme, to openly flout the Overking's edicts, and to enact their own laws and pursue their own mean-minded grudges. It was only a matter of time before Rax was overthrown and a new tyrant installed as Overking and, in truth many petty nobles were glad when it happened. After decades of pointless strife, it was almost a relief to have central power and authority again. However, few of them would have chosen Ivid I as their new master. No direct evidence links lvid, ruler of the North Province at the time with the assassination of the entire House of Rax in 446 CY. But Ivid ensured his ascension by the simple, expedient killing every other minor princeling who made a claim on the throne, and plenty more besides. Madness had gripped the Malachite Throne when lvid I, scion of the House of Naelax, was proclaimed His Celestial Transcendency, Overking of Aerdy, and many knew it.
The Malachite Throne became known as the Fiend-Seeing Throne -- It was whispered that the House of Naelax had willingly entered into a pact with fiends-lords, a pact that would endure down all the generations of their descendants. A time of terror had begun as civil war erupted in the Great Kingdom, we could only pray it would not mean war across the continent.