Galactic Empire
Galactic empires are a fairly common theme in
science fiction. The idea suffers from practical difficulties, not least that it requires
faster-than-light travel to hold the empire together. Nonetheless, many authors have either used a galactic empire as background, or written about the growth or decline of such an empire. Some of these empires are clearly based on the
Roman empire, that in
Isaac Asimov's
Foundation series being an obvious example. The most well known is the
empire from
Star Wars, which was formed from the ashes of the
Galactic Republic.