Long before the current species of Known Space, various other civilisiations ruled over the galaxy. From what little modern archeologists have been able to find, it appears that their technological level was greatly beyond that of any modern, known nation. Prime among these appears to have been the Yareteslani, a species of somewhat humanoid entities who believed themselves to be gods and treated other species like something akin to spoiled pets, giving them anything they could desire. It is unkown what caused the Extinction, but whatever it was, it was quick, sudden and thorough. All technological civilisiations (and according to some estimates, even agricultural ones) were destroyed utterly, their cities raised their monuments defaced and even their megastructures erased from the universe. The most popular theory is that it was a grey goo event of some design. Precious little remains from this time, what there is mostly exists in the form of experiments left behind in the ecology of worlds or even, seemingly, the very fabric of reality itself. Either way, the occasional scraps of technology and culture are considered priceless and worth the attention of entire nations.