Maiden Worlds, or Lilaethan in the Eldar Lexicon, are the lush paradise worlds originally created through advanced terraforming techniques from lifeless Dead Worlds by the Eldar before the Fall of their race's ancient interstellar empire in the 30th Millennium. The creation of these worlds involved seeding formerly barren planets with life, gradually leading to their transformation into lush, life-supporting worlds. The seeding of worlds was part of a program of colonisation which would take many thousands of years to reach fruition, and the result would only be seen by much later generations of Eldar, though in fact many of these worlds ended up being settled by other sentient races like humans and Orks, much to the Eldar's chagrin and anger.