The Sun has gone out. The last remnants of Humanity, Dwarves, Elves, and other sentient races built the massive starship known as Beacon. Lacking any kind of faster-than-light travel, they mined what they could from the planets in their system and set sail for the nearest system that scans had indicated was habitable. The optimists among them thought the journey would take a thousand years. They were wrong.
The length of time from Beacon setting sail from its home system to it arriving in The Cradle of the Alliance is unknown. Time keeping aboard Beacon was strictly kept for the first few hundred years, perhaps a few thousand. But, beyond the lifespans of even the longer-lived of the species that called it home, the timekeeping fell to the wayside and the ships society adapted to survive without it.
After all that time travelling there was much excitement across the colony ship as it arrived in its new system, an excitement that gave into panic as instead of finding an empty plentiful system they were met with an armada assembled by the alliance of systems and planets that call this section of the galaxy home. Of all the things the new arrivals were expecting when they reached this new system the idea that it was already populated was not one that had ever been seriously entertained. The Arrivals had never before encountered a creature not from the same planet as them.
Though some members of the Alliance wanted to greet this unknown ship with missile fire, the more level headed sent a group of council members to greet the ship. Whilst the exact agreement that was made was not written down and only a temporary truce, they returned with a few elders from the Elves, Dwarves, and Humans. A simple peace was brokered before a shot was fired in what would have been a long bitter war, and Beacon was pushed into orbit around the star of the new system which the Arrivals could now begin to integrate into.
The hitch, amongst this whole happy tale, was the Androids. Humans had long ago, with the help of their gods, found a way to craft a machine that was capable of accepting a soul into itself. The Alliance had also discovered this ability, and whilst the rebellion of Androids against humanity had led to their liberation and citizenship, its analogue against the Alliance had gone the other way. Androids, across the Alliance systems, were outlawed. Most were wiped out in the rebellion and the rest were banished to systems outside of the Alliance.
The agreement as it stands, is that new androids are not to be created and existing androids are not allowed to leave Beacon. This unstable situation has been much source of tension in the years since the Arrival and whilst there hasn't been an attempt by the Androids to improve this situation, it is a constant discussion had in taverns and taxi's across the Alliance systems.
The other species that arrived on Beacon have spread throughout the systems. Whilst the majority of them stayed on board as it was retrofitted into a space station, many left to explore and settle across the Alliance and some even strayed further utilising the Alliance developed FTL breach engines.
As the Arrival was such a big event, and the Arrivals had no usable calendar, the Alliance incremented their calendar to the 49th Epoch. The Arrivals instead began their calendar and began tracking time PA, Post-Arrival. (49E and PA are used interchangeably, with 49E being used by cultures that existed across Alliance systems and PA being used on Beacon and the species that arrived with it.)