In the 22nd and 23rd Centuries, the First republic's government and corporate zaibatsu sent tens of thousands of people on interstellar, slower-than-light ships to planets orbiting the stars closest to Earth other than it's own Sun, including the three stars of the Alpha and Proxima Centauri system (4.2 light years from Earth), Barnard's Star (6 light years from Earth), and Wolf 359 (7.7 light years from Earth). These ships traveled at one percent the speed of light, so they would have taken hundreds of years to reach their targets. They included sleeper ships where the crew and passengers were kept in cryogenic sleep for the journey, and generational ships where the children and descendants of the original crew and passengers maintained the ships and became the colonists on new worlds.
After the discovery of the Annunaki jumpgates in 2305, the slow ships and their people were forgotten. After the Universal Church was organized in 2850, it assumed the people on the slow ships were lost to demons in interstellar space ("darkness between the stars"). By the time of the Second Republic, it was assumed that the Republic citizens would never again see the descendants of the First Republic slow ships.
Presumably, if any of the slow ship people made it to their destinations, their colonies would have within a generation or two have sunk to a medieval or even Stone Age level of technology, and would have taken many centuries to even reach a Steam Age/Industrial Revolution tech level. By 5000 A.D., they may have regained space flight, but what if they didn't discover Annunaki jumpgates in their solar systems? Would they have tried to develop a faster version of slower-than-light ship using what is called a Bussard ramjet, which would suck in hydrogen floating in space to power a ship's nuclear fusion engines to up to 80 to 90 percent light speed? Obviously, they would want to return to the ancestral home planet Eartyh, now called Holy Terra.