Humanity’s first attempt to go out among the stars and throw elbows did not end well, but not as badly as it could have. What was accomplished was the complete settlement of our own planet and to a lesser extent the solar system.
The First Emperors of the First Imperium are given credit for perpetuating much of the salutary infrastructure of the Third Fed. The other worlds (Baldur, Osiris, Utopia) were included at the Viceroy level, and local decisions were still more or less democratic.
The Prime Executive (as the Emperor was officially called) derived power from control of interstellar trade and diplomacy. The Terran Empire entered into treaties beyond the just Consortium, and soon became involved in a power struggle within the Consortium itself.
In the midst of that low-level civil war, the Menace returned from a new direction. Once again it was driven away, but the Consortium as an intact political body was fatally divided.
Former allies became enemies, and the Terran Empire, weakened from taking the brunt of the Menace, was forced to retreat back to its home system, granting the other worlds their independence (whether they wanted it or not) and going so far as to destroy the Gates to deter attackers.
When Prime Executive Smile-at-the-Infinite commanded the Gate be destroyed, she then announced that would be her last command. She abdicated – and was not replaced for a thousand years. Instead, Chief Executive duty rotated among the old Third Fed Viceroys, as they cobbled together a government that could survive without interstellar trade, or the urgency of war.
Absent of interstellar distractions, the people of Earth turned to their dying planet, and poured their remaining (if dwindling) resources into saving it. This is the era when megapoli became macropoli – cities the size of states. Water sources were systematically covered up to maintain cleanliness and prevent evaporation. The coasts became enormous fortresses of tide-control constructs. Solar and geothermal power was maximized, and matter/antimatter was refined to the consumer level. Weather patterns became so chaotic and hostile that humanity found it easier to simply farm indoors, in city-sized greenhouse complexes. Even wilderness areas were sealed under domes to preserve what was left of nature from what nature was becoming.
By the end of the Long Night, humanity had solved global warming by building over the planet, and then air-conditioning it.
The first permanent residents of Venus appear in this time and the super-orbitals of New Earth (opposite side of Earth’s orbit) and New Jupiter Station (or NuJo) were completed.
Overlord was the adopted name of the Emperor who sought to take humanity back to the stars. He was a Viceroy who refused to pass the Executive duties around at the end of his turn, and had accumulated enough martial resources to make that decision stick. He then looked outward. Armed with an economy that was finally solvent again, he pursued that hoary dream of true hyperspace drive, knowing that Humanity once was on the right track before the Consortium stopped them[1].
It was feared at the time that his exertions in this quest would impoverish the entire planet before it succeeded, but the gamble paid off. The first hyperspace warships began to visit Earth’s neighbors and found that they, too, were weak and struggling. So Overlord promptly began a war of conquest, leading the assault fleet in person.
In his absence, he was deposed, while his fleet, inevitably overextended, was slowly destroyed.