Sol is the cradle of human civilization. It is the location from which humanity reached forth into the galaxy. Like all cradles we eventually grew to big for it, and when we left it to go to the stars, only the dregs of human society remained behind. In 2285 The Holy Roman Church began a program to clear the system of any non-Christians. This project was finally completed in 2330, and from that point forward only true believers are allowed within the system.
There are some small Labor Enclaves within the system, mostly in the Asteroid Belt and the Kuiper Belt, or on the Gas-Mining stations of Jupiter and Saturn. These locations contain a variety of Laity, but Earth is only permanently inhabited by the Roman Curia. The richest member of The Ordained and The Laity are allowed to make pilgrimages to Earth, but none may stay permanently. Earth is considered to sacred and fragile to allow just anyone to live there.