The Great Migrations is a general term applying to the migration of great hordes of Oeridians and Suel humans into the Flanaess from western Oerik. The impetus for the migrations was political tension related to the conflict that erupted into the great Baklunish-Suloise Wars that ended in the Twin Cataclysms. The passage of these thousands of refugees displaced and destroyed much of the local Flan culture and shaped the modern Flanaess.
The Oeridian tribes began migrating east of the region now called Ull circa -465 CY (tAB, 55), pushed north and eastward by vast savage humanoid hordes employed as mercenaries by the Suel and Baklunish. Suel peoples fleeing the increasingly erratic empire moved northward through the Kendeen (Harsh) Pass of the southern Crystalmists (now the Hellfurnaces) and spread out in all directions, coming into open conflict with the native Flan of the eastern lands and with the migrating Oeridians. In most cases the warlike Oeridians defeated Suel and Flan alike, pushing them to the peripheries and darkened wild places of the Flanaess.
A large number of savage humanoids followed in the wake of the migrating hordes, infecting the Flanaess with a brutal violence it had previously been spared.
Open hostitilites between migrating factions persisted for two centuries, with notable pockets of Suel/Oeridian cooperation in places like the Sheldomar Valley. Four of the mightiest Suel clans pushed into the Thillonrian Peninsula, where they remained isolated for hundreds of years. Most Suel were pushed to the extreme southern reaches such as the Tilvanot Peninsula, the Amedio Jungle, the Duxchan Islands, and Hepmonaland. Oeridians usually mastered conflicts with the Suel due to their friendship with the native elves, gnomes, dwarves, and halflings of the Flanaess, to say nothing of the Flan themselves.
The strongest Oeridian tribe, the Aerdi, settled the land east of the Lake of Unknown Depths and founded the Kingdom of Aerdy, which eventually became the Great Kingdom. The formation of Aerdy is generally considered the end of the Great Migrations period.
Migrations era tribes, houses, and political entities
The following political entities were extant in the era of the Great Migrations.
- Kingdom of Ahlissa (Flan)
- Kingdom of Carashast (Oeridian)
- Barony of Lum the Mad (Oeridian)
- Medegian Bladelands (Oeridian)
- Kingdom of Thalland (Oeridian)
- Kingdom of Tuerny the Merciless (Oeridian)
- Empire of Vecna (Flan)
- House Cruski
- House Fruztii
- House Linth
- House Lizhal
- House Malhel
- House Maure
- House Neheli
- House Rhola
- House Schnai
- House Zelrad
- Gygax, Gary. World of Greyhawk Fantasy Game Setting. Lake Geneva, WI: TSR, 1983.
- Holian, Gary, Erik Mona, Sean K. Reynolds, and Frederick Weining. Living Greyhawk Gazetteer. Renton, WA: Wizards of the Coast, 2000.