Fall of an Empire

The human Empire which has lasted among the Stars for a millenia has finally fallen, some say it was the collapse of their economy which led to their downfall with unscrupulous aliens taking advantage of the humans, the Empire's allies refusing to bail them out in any fashion. Yet others say that there have been illnesses that have defied any attempt to cure by the best scientists in the Empire, no matter what they attempted it invariably failed, on occasion they thought there was a cure only to have whatever was causing the illness to evolve and continue stronger than before. Regardless of the reasons for the downfall, the human race which inhabited over four dozen worlds was reduced to only one, though not earth, as it began a quarantine of its borders as soon as they heard of the sickness that was plaguing its outer colonies, communications from the homeworld ceased two months after the quarantine started, ninety years ago.