The Earthbound Universe — A Universe from the Mind of Unca D

Approximately 200 years from now the first starship to colonize a habitable planet orbiting a nearby star is launched. En route a timespace drive incident threw the ship off course -- hundreds of lightyears from either Earth or the proposed colony planet, and 5,000 years in the past. The crew located another habitable planet and the ship headed there, where the colony was formed and eventually thrived. Now,5,000 years later the colony has grown into a hegemony of a dozen colony planets. Wary of the time-travel paradox, the citizens of this empire dare not reveal their existence to Earth until after the original mission was launched.