Page "Philosopher's stone" Paragraph 8

The 16th-century Swiss alchemist Paracelsus ( Philippus Aureolus Theophrastus Bombastus von Hohenheim ) believed in the existence of alkahest, which he thought to be an undiscovered element from which all other elements ( earth, fire, water, air ) were simply derivative forms.

Paracelsus believed that this element was, in fact, the philosopher's stone.