Sillage

Sillage (called Wake in English-language editions) was a vast convoy of spacecraft that constantly travel around the galaxy in search of resources, new species, and technology. The convoy dropped hyperspace teleporters as it travelled, allowing instantaneous access to previously visited star systems.

Sillage existed for millenia (with hints existing that it circled the galaxy many times) and revisited many stellar systems over time periods sufficient to watch entire civilizations rise and fall. There was also evidence that Sillage terraformed planets and seeded life on them over time.

Government
Sillage was officially ruled by the Constituante, a council of the most powerful (usually more telepathic) species in the convoy.