Paracelsus was a Swiss-born physician and alchemist. Practicing medicine as he wandered across Renaissance Europe and using minerals as medicines, he is regarded as a forerunner of modern medicine and chemistry. He tried to put alchemy to use in medicine, and a book attributed to him describes how to make a homunculus.
In his posthumously published Book on Nymphs, Sylphs, Pygmies, and Salamanders, and on the Other Spirits, he taught that spirits live in each of the four elements of water, air, earth and fire. These became the “four elemental spirits,” the undine, sylph, gnome and salamander, which greatly influenced later fantasy works.