While searching through your old forums, I found this 95% finished, most interesting text by Sload. (Original thread)
From what I can tell, it has not been included into TR, but since it is excellent background lore for the Great Houses, I post it here as a reminder, perhaps you have some use for it. Two images are missing, otherwise it appears to be finished.
History of the Great Houses
by Hasphat Antabolis
The ancient culture of the Chimer (tr. 'Crafty Folk') was, like many elven societies, dominated by clannish kinship groups. As the peoples of Dwemereth evolved and developed sedentary ways of life, the native name for these clans became the same word for "hearth" or "home;" hence today, in translation, the structures which have evolved from these clans are known as "the Great Houses." (Hereafter I will avoid philological digressions.)
In the so-called First Council period, there were not five or six but dozens - possibly well over one hundred - house-clans worthy enough of note that they could be attested in record. Many of these have left major traces on the history of Morrowind; not only those which evolved into Great Houses (such as Llalu, later Hlaalu, or Indr-El, later Indoril), but also others (such as Sotha, clan of Sotha Sil the Magus). Later authors have made reference to the "Seven Houses of the First Council." This is ahistorical arising from ignorance (in the case of Western researchers) or religious revisionisms (in the case of native propagandists).
During the long reign of the Tribunal Temple that the many house-clans coalesced into a small number of Great Houses. Most were subsummed into the massive House Indoril, the House most closely associated with the trappings of power. Some of the southern houses formed a confederacy, becoming House Dres. House Hlaalu is a merger of a few houses from Morrowind's south-west. House Redoran developed its own traditions along Morrowind's rugged frontier with Skyrim. House Telvanni was one of the latest house-clan to form, arising among heretics in the distant islands which take its name.
It was only after these monolithic Houses came into existence and stabilized that they became known as Great Houses. The Great Houses became associated with particular roles in Dark Elf society, or aspects of Dark Elf identity, as a result of theological advancement during the early Second Era. Around the time of the Potentacy, cosmological schema such as "The Five Cornered House" or "The Wheel of the Tribunal" (both reproduced below) became popular, providing teleological & moral justification for the existence of the Great Houses.
[Image: The Five Cornered House]
[Image: The Wheel of the Tribunal]
Since the Armistice, the order of the Great Houses has been somewhat disturbed. The Indoril's self-perception as the central and most authoritative House has been disrupted by the advancement of the Hlaalu at their expense. The Redoran, once the staunch defenders of the country's borders, struggle to find a new role after Morrowind's integration into the cosmopolitan Empire. The Dres & Telvanni cling to outmoded customs, including nemer slavery, which are beginning to be challenged by outsiders. The Great House system has proven to be unstable in these changing times, and its future is very uncertain.
Description of the images from original thread (quote by Sload):
The Wheel of the Tribunal Description:
A wheel with six spokes, the symbol & name of each house at the point where a spoke hits the wheel. The center of the spokes is the Tribunal, each spoke is identified (twice, on either side of the center), with a tribunal. The specific arrangement is:
Spoke 1 (top to bottom): Vivec; House Redoran @ the top, House Dagoth @ the bottom
Spoke 2 (upper left to lower right): Almalexia; House Indoril @ upper left, House Hlaalu @ lower right
Spoke 3 (lower left to upper right): Sotha Sil; House Dres @ upper right, House Telvanni @ lower left.
The Five-Cornered House
A pentagon (upright), with a Velothi-type clay hearth in the center of it. Along the outside edges of the pentagon are written these words:
Upper-left: Redoran, Warden
Upper-right: Indoril, Lawgiver
Lower-right: Dres, Upholder
Bottom: Telvanni, Cynic
Lower-left: Hlaalu, False Denier