The Fall and Recovery (Patreon)

The Fall lasted twelve hundred years, a sizeable dark age and one who lasted so long due to a large confluence of factors.

The first and most well known one is the disappearance of hyperspace, causing the complete stop of interstellar travel, the collapse of the Federation's communication network and the destruction of all of its advanced computer systems, who were partially energy state and thus nestled in hyperspace. Some, like AI cores, were made to have solid state data storage for legal reasons, others...did not. This caused a massive loss of knowledge but also the annihilation of most planetary information systems.

The next one is the change in conductivity. This affected most baseline technology, and while not utterly crippling, it brought the electric age to a grinding halt, causing most power plants to go into emergency shutdown and many computerised machines to fail. This included almost everything from hydroponics to food processing plants and steel smelters, causing advanced civilization and, more importantly, the ability to sustain the populations the Federation had on its worlds, to utterly vanish.

The famine caused by both of these phenomenon only compounded the collapse. People began doing whatever was necessary to feed themselves and law and order vanished. In less than a year, hunger had reduced most worlds' population to a tenth of their previous size.

But within a decade, societies began to climb back up. Many colonies were organizing the people that had useful knowledge, piecing back what was lost and rediscovering basic metalworking.

Then the monsters began to appear, as magic truly seeped in. Suddenly settlements on paradise worlds, where no pests or other dangers existed, as why would they have been introduced in the first place, and whom had been under an oppressive regime where personal weaponry was forbidden were faced with rapidly evolving, highly hostile wildlife and mutating plants.

This crippled the rapid, early recovery, pushing true rebuilding well into the second and third century, as people scrambled to survive and most of the old knowledge was lost or distorted in oral histories, and magic began to emerge among the population.

Once metalworking was mastered once more, technological rediscovery hit a new hurdle : most, if not all, of the interstellar colonies lacked any fossile fuel to speak of. Coal and oil were formed by long dead lifeforms, and were completely lacking on those worlds. Without them, steelmaking and various other products such as advanced fuels, steam engines, synthetic fibers and plastics were either nonexistent or massively more expensive and problematic to manufacture at all, let alone in the quantities required for advanced technologies, further slowing down progress.

Last, but not the least, the appearance of mages and magic massivel slowed, if not put a stop to, technological progress. Since mages, engineers and scientists draw from roughly the same, limited, pool of people, any mage thus detracted from the others. Furthermore, there were considerable incentives to go down this path. Mages are well respected, personally extremely powerful and systematically highly important members of their community. Not to mention, magical solutions were often far simpler to put into place than technological ones, and once they were, there was great incentive by the existing mages to not seek to replace themselves or their achievements with mundane alternatives or allow others to do so.