The Wars and Restoration (20c. to 21c.)

Global wars of the 20th and early 21st centuries left much of the world's societies devastated. In order to recover quickly and reforge stability, a trio of beleaguered superpowers merged into a federated superstate known as the Trinity, slowly expanding at they integrated other surviving states with offers of recovery and protection.
As the next few decades progressed, and the scale of the cleanup efforts were calculated, Trinity began to look upward towards the other bodies of the solar system. The Wars had brought enormous advances in technology, chief amongst them solid-state thermal harvesting devices and miniaturised fusion. With these technologies, Trinity sought the vast wealth of the solar system to aid Earth's recovery effort.

Permanent colonies were established first on the moon, providing a staging area for further construction and exploration, and then Mars as the new frontier of humanity. Automated mining operations were established across the solar system, bringing home hoards of materials never before imagined.
To bridge the gap between space and Earth, Trinity leveraged the materials science advances of the Wars to build the first Spires on Earth and Mars, space elevators that made the transfer of goods and personnel to and from the planets’ surfaces cheaper and easier than ever before. Through its control of the Spires and the vast economic system that ran through them, the Trinity forever entrenched itself as the dominant political power over any remaining holdouts.

The Solar Golden Age (22c.)

By the start of the 22nd century, huge advances in propulsion has been made, including electrostatic jet propulsion and extremely efficient orbital engines. A new generation of cheap transorbital shuttles and vast, modular spacecraft expanded local space travel like never before. Private enterprises large and small were quickly able to compete with state enterprises for interplanetary shipping and industry, though the incredible economy of scale of the Trinity-controlled Spires cemented the state's control over Earth and Martian transorbital logistics.
Eventually, the century of humanity's solar golden age drew to a close. Earth had been restored as best as could be done, Mars had developed into a major colony rivalling many pre-War first-world states, and human control and economic exploitation had been solidified across the solar system.

Reaching to the Stars (23c.)

With their work in humanity's cradle completed, Trinity once again looked further afield. A series of automated constructor fleets were built and launched towards humanity's closest habitable stars, using advancements in engine technology to reach closer to lightspeed than ever before. The fleets were programmed to construct self-sufficient outpost colonies in preparation for eventual human arrival.
As the fleets traversed the interstellar void and began their toil, Trinity scientists finally closed in on the holy grail of space travel; faster-than-light technology. Using machinery developed from secret experimental weapons from the wars, the first controlled artificial wormholes were produced, and over the following years the technology was refined to the point of supporting stable, reliable transit of bulk goods and even living beings.

The Trinity government then took the next bold step of constructing the first pair of generally-practical Spacefold Gates, as they were now popularly dubbed, between Earth and Martian orbits. After many months of round-the-clock testing, humanity's first interplanetary portal was opened and the travel time between its first and second homes was shrunk to less than a day.
With humanity's first venture into FTL travel a resounding success, Trinity looked towards the in-construction colony on Proxima Centauri b. Construction plans for a Gate were transmitted to the system's constructor fleet and a second Gate was quickly commissioned in Earth orbit. A year later the first interstellar Spacefold route opened and humanity officially reached beyond the cradle of its home star.

The Birth of the Gate Network (23c. to 24c.)

From its experience with the post-War period and the Spires, the Trinity establishment knew it had to consolidate power over the Gate network to survive. It took its experience from the Proxima Centauri project and designed new fleets of self-replicating constructors with a new purpose. They were launched in the 2270s on an endless journey outwards from Sol, replicating themselves en-route to new stars and seeding those systems with constructors ready to build new Gates.
With the primary fleets now able to pass systems by and leave their offspring to decelerate into the system, a broad web of Spacefold routes spread out from Sol at an appreciable fraction of lightspeed, and with the Gates remaining legally and technologically under direct Trinity control the superstate's reach over human space was forever secured.

As the first new Gates came online, travel time between even stars dozens of lightyears away was reduced to a matter of days or weeks of intra-system travel between Gates. Colonisation efforts flourished as Trinity sought to push humanity's footprint further and further, establishing new enormous mining and research efforts and numerous support colonies en-route between these new destinations and Sol.
Initially, all extrasolar colonies were directly commissioned and overseen by the Trinity state, but as the decades passed and humanity's reach grew, the workload of administrating dozens of distant colonies threatened to swallow Trinity's bureaucratic capacity. A new paradigm was sorely needed to service humanity's rapid expansion. The solution to this problem finally came in the mid-24th century in the form of the Frontier Worlds Act, a sweeping reform of Trinity's extrasolar colonisation efforts.

The Frontier Worlds Act (24c. to present)

The Act's first provision was the privatisation of colonisation rights. The constructor fleets and the Spacefold Gate network would remain under state ownership, but the rights to any worlds discovered and surveyed by the fleets would be put to public auction.
Planetary surveying, far surpassing in detail the cursory scans the constructors performed, quickly exploded into a major industry, and corporations fought bitterly to purchase new homeworlds near their centres of income.
While a great many academics and activists, both at the time and in the years since, have criticised the first provision as producing countless doomed colonies and leaving vast swathes of space undeveloped due to lack of financial returns, no-one can deny the Act stimulated private interest in space development like never before.

The other major change brought about by the Frontier Worlds Act was the subdivision and devolution of known space into 5 regions, each then subdivided into countless sectors.
The existing region of heavily-colonised space was designated the Central Sectors region, and the ring of space around it was split into 4 equal segments along the coreward/anticoreward and spinward/antispinward directions.

The Spinward Sectors region, clockwise along the galactic disc, was already the most populated and developed of the areas outside Central Sectors, and quickly gained the informal title of Mankind's Garden.

The Outward Sectors region, away from the galactic centre, was the first to be opened to auction and thus received the lion's share of the initial surge of private investment and development, marketing and media around the FWA dubbing the region New Hope.

The Inward Sectors region saw less development than Mankind's Garden or New Hope, but a secondary wave of interest from new industries looking to make a name quickly garnered for it the nickname of The Crucible.

The Antispinward Sectors region, the last to be auctioned well after interest had waned and demand had been sated, quickly faltered in its development. Corporations saw little reason to invest so far from the established centres of power and industry, and the few that did take a chance on the region were more enamoured with the novelty than any actual benefit it offered. The region quickly became a graveyard for ill-conceived ventures and doomed get-rich-quick schemes, before morphing into a home for niche affinity communities seeking a homeworld of their own, ethnic minorities and refugees from the more populated regions looking for the safety of solitude, and the inevitable clawed grip of piracy and organised crime. Over time the region's reputation became widespread, and it began to be spoken of simply as The Backwaters.