The House Founders are the nine original Sidhe, the first of their kind to enter Arcadia. Previously they were the stars which lit the Dreaming.
Each of these Sidhe founded a house which took their name. All Sidhe bear the nature of their House Founder, in addition to any particular nature of their own.
After arriving in Arcadia, each of the House Founders went off on their own. Their adventures during this period were fundamental to the later history of the Dreaming.