Capital is on Cyteen. Only Humans are full citizens. The bulk of the population are thus without full citizenship as they are genetic engineered Azi. The rulers in the Council of Nine are altered to live for thousands of years.
When space erupted in rebellion against the dominance of Earth Company a group of dissident scientists and engineers founded a colony on Cyteen. On Cyteen the first Faster then Light-vessels were constructed. Declared independence in 2300 from Earth Company.
This prompted Earth to build their own FTL-ships, military ships, in an effort to bring back dissident stations back into line. This failed and together with the formation of the Merchanter's Alliance and the subsequent Treaty of Pell, the Union was accepted as a third human political power.
Society on Cyteen is based on the genetic engineering of specialized workers, engineers, soldiers etc (Azi).