Yliaster or Iliaster, a term coined by

Paracelsus Paracelsus (; ; 1493 – 24 September 1541), born Theophrastus von Hohenheim (full name Philippus Aureolus Theophrastus Bombastus von Hohenheim), was a Swiss physician, alchemist, lay theologian, and philosopher of the German Renaissance. H ...

, refers to "prime matter, consisting of body and soul". Paracelsus described the Iliaster as the "completely healed human being who has burned away all the dross of his lower being and is free to fly as the Phoenix."The Complete Idiot's Guide to Alchemy
/ref> It is most likely a portmanteau of the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

'' hyle'' (matter) and

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''astrum'' (star). To Paracelsus, the Iliaster represented the two basic compounds of the cosmos, matter representing "below", and the stars representing "above". Paracelsus says this of the Yliaster while describing how fossils are trapped in wood: In this sense, the Yliaster is the same as the

Prima Materia In alchemy and philosophy, prima materia, materia prima or first matter (for a philosophical exposition refer to: Prime Matter), is the ubiquitous starting material required for the alchemical magnum opus and the creation of the philosopher' ...

. It is the formless base of all matter which is the raw material for the alchemical Great Work.

References

Alchemical substances Mythological substances {{chem-hist-stub