The Galactic Empire-Adronus Encyclopedia.

The Galactic Empire was formed in the post-orsorsus days by a foreign and mysterious person.  Archaeologists discovered an ancient tablet on the urub planet of Inco, with the emperor's name on it, Tal'quurssri-eram, a name from none of the languages within the Adronus galaxy.  Some centuries after the orsorsus, and long before modern humans, Tal came from a galaxy not far from the Adronus, in a strange living crystal ship, and landed on the empty tomb world of Orveneus prime, from there, he went to Dius.  He gathered a small army, and slowly conquered Dius, than it's twin, Ius.  Tal started to gather an enormous army, to carry out his plan, a galactic empire, he claimed all the planets along the Galxthr Run and the Urub Spice Lane.  His empire grew even more, until it covered the whole galaxy.  And it was Tal who was angered by the inhabitants of Tezva, and partially destroyed their world.  Tal came from a very long lived race, and a tough race, many assassins tried to kill the emperor, none succeeded.  Then, a g'ul stargazer foretold the fall of the Empire, which by then had lasted  two thousand years, and not long after, a human warlord led an army to Dius and destroyed the capital, but the emperor fled to his secret fort on Kerron, and there the Galactic Empire had it's last stand, but in the long, bloody battle, the human Zunn, cut of Tal's head.  The remnants of the Empire were picked of by barbarians, but along with the fall of the Empire, hyperdrive technology was lost, until finally reinvented by tua and galxthoricans.  The only two species able to avoid Empire control, were the uruzad, a radioactive race, and the carisytes, parasitic species.

A note on Galactic Empire technology:  though the Empire used space flight, until it was lost for several hundred years, otherwise, they used simple steam or coal powered machinery, but used swords, spears, bows and arrows and metal armor in warfare.