Notes:

The Swiss German physician and alchemist Paracelsus first coined the term Sylph in the 16th century to describe an air spirit in his overarching scheme of elemental spirits associated with the four Classical elements.

Paracelsus drew from earlier sources, but his systematic treatment of the idea was definitive, with the names of three of the four types having originated in his works. The other three elemental spirits named were Gnomes (earth), Salamanders (fire), and Undines (water).

These ideas were adopted in Rosicrucianism and were widely encountered in subsequent hermetic literature.

In the Liber de Nymphis of the Philosophia Magna, Paracelsus discusses the characteristics of the elementals at length.

Sylphs, he says, are rougher, coarser, taller, and stronger than humans. The elementals are said to be able to move through their own elements as human beings move through air.

Because of this, sylphs are the closest to humans in his conception because they move through air like we do, while in fire they burn, in water they drown, and in earth, they get stuck.