"It was scarcely a million years subsequent to this epoch [400 billion years ago] that Michael of Nebadon, a Creator Son of Paradise, selected this disintegrating nebula [Andronover] as the site of his adventure in universe building. Almost immediately the architectural worlds of Salvington and the one hundred constellation headquarters groups of planets were begun. It required almost one million years to complete these clusters of specially created worlds. The local system headquarters planets were constructed over a period extending from that time to about five billion years ago."  57:3

"The Melchizedeks occupy a world of their own near Salvington, the universe headquarters. This sphere, by name Melchizedek, is the pilot world of the Salvington circuit of seventy primary spheres, each of which is encircled by six tributary spheres devoted to specialized activities. These marvelous spheres — seventy primaries and 420 tributaries — are often spoken of as the Melchizedek University. Ascending mortals from all the constellations of Nebadon pass through training on all 490 worlds in the acquirement of residential status on Salvington. But the education of ascenders is only one phase of the manifold activities taking place on the Salvington cluster of architectural spheres."

"In passing through the seven mansion worlds, you will also progress through these cultural and social spheres of increasing morontia contact. When you advance from the first to the second mansion world, you will become eligible for a visitor’s permit to transitional headquarters number two, the morontia world, and so on. And when present on any one of these six cultural spheres, you may, on invitation, become a visitor and observer on any of the seven surrounding worlds of associated group activities."