Pleiades Empire
Around the year 2380 AD, a spaceship consisting of a massive hollowed out asteroid, with 100,000 selected colonists, and the sum of all human knowledge left earth.
A few centuries later they found themselves near the center of the Pleiades cluster, close to a solar system with a planet with water, a breathable atmosphere, and plants. A small group of colonists moved to the planet but the majority stayed in the asteroid, where there were gardens, factories, and nuclear power.
A rogue asteroid threatened the colony ship so they intercepted it, and discovered some crystals with unusual properties. Two of the types of crystals allowed them to colonize the cluster. The one type had a gravity neutralization effect. The other type allowed them to make matched pairs of jump gates.
The gravity neutralization crystals allowed for a functioning space elevator. They sent an unmanned ship with one of a pair of jump gates out to then nearest star at sub-light speed. Fifty years later, the ship arrived at the neighboring star, which allowed instantaneous relocation between the two gates and to the next system. From there, they sent the next jump gate onward.
The discovery of the jump gate crystals was what really kicked of the forming of an empire. The grandson of the original colony leader was bullied into accepting the title of emperor. The population also pushed for a form of primogeniture, where the oldest male inherits everything.
The descendants of the original shareholders who built the New Horizons became the first nobility (Emperor, duke, viscount, baron). Knights (Knight Protector of ) were appointed, but were not hereditary.
The Pleiades Empire stories takes place around 1400 years after humanity first arrived in the cluster.