Ancient and powerful aristocratic establishments and bloodlines going back thousands of years, each House is also a clade or race with its own rules and culture and religion, its own protocol and ontology and rich tradition, and its own guiding and overseeing transapients (whether AI, posthuman, postvec, postalien, or postprovolve). You cannot just join a Great House, you have to born into it, and carry the divine sangreal or the sacred code. Here baroque feudalism and noblesse oblige is the standard of society, as it has been for centuries.
Historically, the Houses as a monarchic or oligarchic system of government originated among the colonies with the decline of the First Federation, reaching maximal influence during the Age of Emergence. From the beginning, competition was intense, especially in the old Federation, and only the most intelligent or the most ruthless were able to flourish. In the Inner Sphere many of the Houses were later absorbed into, or became client states of, the great archailect empires. A few powerful Houses like Cygexpa, Metasoft, and Silicon Generation became independent superbright and hyperturing empires in their own right. Others fled to the periphery to try their luck in the new worlds. The rest continued as quaint institutions, local baronets, or eccentric micro-principalities living on the memory of former glories. Since the Empires period, throughout the Inner Sphere and the developed provinces, the House system has been limited to a local or clade-pride phenomenon, sometimes with economic or diplomatic overtones, rather than a political-military form of government in its own right. These institutions are sometimes valued by the hyperturing authorities for memetic purposes or as means of entertaining the masses with spectacles of royalty. In other systems they are barely tolerated and have to eke out a living on mined-out asteroids or in kuiper bodies or comet cores. Away from the reach of the mighty hyperturings and overruling Archailects however, the situation is very different, and in many of the more isolated areas of the Hinteregions, throughout the less developed Outer Volumes, and along the Periphery, the House system flourishes as much as it had during the late First Federation period. But as the AI Gods extend their reach outwards, many of these ancient monarchic regimes are forced to resettle and develop even further out, and once again reestablish local sovereignty.
Adapawe Clan - Text by Stephen Inniss A wealthy and influential clan of Inner SphereSuperiors, best known for the role they have long had as Shareholders in Cygexpa. The ongoing feud between the Adapawes and their Veiler allies and Adriana Yue's Shareholder faction is thought to have contributed to the great Cygexpa sell-off.
Aeoina - Text by Anders Sandberg Cygexba client house, composed of nanocyborgs and artificially evolved neural net entities.
Akirate Stevens - Text by Anders Sandberg Breakaway clade from House Stevens. Joined the Solar Dominion and later in the Version War helped several raids on Stevens worlds. Has since slowly but steadily diverged culturally from the original House, growing ever more into a cyborg-AI symbiosis culture.
House Claida - Text by Anders Sandberg Minor non-aligned house, descended from the Claida family fortune. The Claida relativists created an insurance-arbitration empire in the late ComEmp era that has diversified and persisted to this day. Traditional ceoship is left to the Rojmaneo, the head of the clan and the only member allowed full interface with the Claida ancestral gnostic overlays.
Marabi Patha, House - Text by M. Alan Kazlev Mildly tweaked hereditary leadership, Based at Thorne Biosphere, Schilowa World, Mathilde system, near Hyperion (world). Rose and fell during the Age of Empires.
Veiler - Text by Anders Sandberg Shareholder group from the Veil Nebula worlds of Cygexba. Originally based on the shares owned and invested by Incenti Jerwan during the late consolidation era which became owned by the Bank of Aucygnus after his bankruptcy. The Bank leveraged the shares into a controlling position of the local wormhole links, producing both enormous revenue and a long-running low-level dispute with the Friedmen. Over the centuries the bank became a democratic shareholder-house, largely supporting the slow expansion and political control advocated by the Adapawe.