The role of the sixth House, House Dagoth, is not fully understood. Resdayn flourished for a few hundred years until the War of the First Council broke out between the secular Dwemer and the orthodox Chimer Houses Indoril, Redoran, Dres, Hlaalu, and Telvanni. Nerevar and the Dwemer leader Dumac Dwarfking subsequently created the First Council of Resdayn to jointly rule the area as an independent nation. In 1E 416, following almost two centuries of suppression by the ruling Nords, the Chimeri hero Indoril Nerevar united the squabbling Great Houses as Hortator, also making alliance with the Dwemer, their traditional enemies, and succeeded in driving the Nords out of the region. They abandoned their former nomadic lifestyle, and divided themselves into political clans, which would become the Great Houses Indoril, Redoran, Telvanni, Hlaalu, Dres and Dagoth. The Great Houses have their origin in the ancient customs of the Chimer, a self-exiled Aldmeri sect who followed their prophet Veloth across Tamriel from the west. It has been known for a single dissenting councilor to fight a potential hortator candidate in a duel to the death, thus protecting the honor of the councilor if they win or proving the candidate's ability if they lose. Election of a hortator requires unanimous consent among all councilors. In times of extreme danger, house councilors may choose to elect a 'hortator' who has the ability to make decisions on behalf of the House as a whole. Finding a councilor to sponsor an outlander often involves performing a great service for the prospective sponsor and the Great House in question. Adoption and advancement to higher ranks in a Great House requires that a Great House councilor stand as sponsor for the candidate's character and loyalty.

Later, after faithful service and advancement in lower ranks, an outlander may seek adoption into a Great House. Initially an outlander may gain status in a house as an oath-bonded hireling, pledging exclusive loyalty to a single house and forsaking ambitions with all other houses. Even if one gets kicked out of one house, no other house will have them. When joining, one becomes family, and, by Dunmer standards, it's a matter of blood and kin, and irreversible. Loyalty is very important in the Great Houses. Those seeking to join a Great House are implored to think carefully before choosing, as once one has joined a House, no other House will ever consider them for membership. Dunmer Great House membership is largely a matter of birth and marriage, but outlanders may also become retainers of a Great House, or may be adopted into a Great House.

Morrowind great house dagoth mod