The Galactic Empire was a fascist government which ruled over almost the entire extension of the galaxy for a period of 23 years, following the fall of the Galactic Republic as Darth Sidious seized power; and lasting until his death. The Imperial military forces consist mainly of soldiers called Stormtroopers.
During the Empire's reign, Humans were the dominant species of the galaxy, as most aliens were persecuted, and the majority of common citizens - both Human and non-Human - tended to live in a state of political repression, poverty and fear.