Thronespace like many other Crytal Orbs was formed by the Gods as a fortress against the Titans in the God/Elder Wars.

Thronespace was the main battle camp of the Forces of the Gods, the Throne at the time was passed from Greater God to next via some schedule of their devising. this sharing worked only so long as the battle against the titans was joined.
in time of PAX this made the holder of the seat to powerful, twice it required the combined might of the lesser, and demi thrones to remove a god who refuse to release the Great Throne to the next holder.  After the second time and blood was spilled the gods Forged a Great Pax, and Banished them selves from the Orb.