The Infinite Empire was what was before the Old Republic. It was run by the Rakata, who were jerks. They came from the planet Lehon, which is refreshing that they weren't just called the Lehonians. They somehow were able to use the Force to create weapons of great power, such as the improbable Star Forge, and could dominate everyone else, including lowly humans. This went on for thousands of years. One human slave, named Tim Spartacus, wrote a book called "Infinite Empire My Ass!", which became hugely popular among enslaved civilizations. This annoyed and the Rakatans. The annoyance led to anger, which led to hate, which led to suffering, which led to stupidity, so eventually the Rakata ability to control the Force diminished, until it destroyed them. The rest of the galaxy was quite pleased about this turn of events, but humans seemed to be the ones most interested in filling the void, so they took over the place. The first thing the humans did after establishing the Republic was to delete all records of the Rakata civilization, however, they forgot to delete their cookies in their web browser, and somehow this kept the information long enough for people to learn that the Rakatan survived in isolation for a few thousand years before finally becoming extinct.