Sith Empire (Pre-Republic)

The Sith Empire was established by the Sith (species of Korriban circa 28,000 BBY, following the defeat of their Rakata invaders under the leadership of Adas. Having united all of Korriban under one rule, Adas was given the title of Sith'ari, or Lord of the Sith. Taking what remained of their enemies' spacecraft, the previously primitive Sith -- now instantly propelled into a space age and armed with the dark side of the Force, both acquired from the Rakata -- went on to conquer other nearby worlds, in what would later come to be known as Sith Space, their capital being relocated from Korriban to the neighboring Ziost.

It is unknown for how long the empire thrived, but it was long gone by the arrival of the Exiles in 6,900 BBY; and the Sith had once again devolved into a primitive people.