Quendor was the kingdom predecessor of the Great Underground Empire.
Entharion the Wise united the warring city-states of Galepath and Mareilon, forming the Kingdom of Quendor in 1 GUE. It was a kingdom little more than the present province of Frobozz. As the first king of a long dynasty, Entharion ruled from Largoneth Castle.
Little is known about the early years of the kingdom. Eventually the war-like nature of the early city-states was forgotten, and they all united for good under the brown and gold flag of Quendor.
In 659 GUE, the kingdom was still relatively small, encompassing 7.5 provinces on the western shore of the Great Sea, an agrarian land whose major products were rope and mosquito netting. It was the 31st year of the reign of Zilbo III, the last king of the Entharion Dynasty, which abruptly came to an end with the ascension of Duncanthrax to the throne of Quendor on the final day of that year.
After removing Zilbo, Duncanthrax quickly developed a reputation for cruelty, bloodthirstiness and aggressiveness, thus earning himself the nickname "The Bellicose King." He raised a tremendous army and began a systematic conquest of the neighboring kingdoms. Within three years, the empire controlled virtually all the land between the Great Sea and the Kovalli Desert. It was during this period that the new king moved the seat of power from Largoneth to Egreth.
As he absorbed the new territory into the kingdom, Duncanthrax discovered huge caverns and tunnels in the Eastlands which inspired his imagination since by burrowing into the ground he could multiply the size of his empire. In 668 GUE he created the Frobozz Magic Construction Company and the natural caverns in the eastern lands were expanded tremendously. New caverns and passages were dug in the western lands, chiefly in the vicinity of Egreth Castle. By the time of his death in 688 GUE, Quendor encompassed virtually all territory in the known world, above and below ground.
After Duncanthrax, the throne was occupied by a long series of his descendants, unspectacular rulers, who took on the surname Flathead, for obscure reasons (not necessarily related to the planar shape of their pates). The conquered kingdoms were assimilated into Quendor and the frantic pace of tunneling gradually abated.
The decline came during the reign of Lord Dimwit Flathead during the eighth century. He became the first to call Quendor "The Great Underground Empire,"