Rosicrucians in the context of Societas Rosicruciana in Anglia

Paracelsus (/ˌpærəˈsɛlsəs/; German: [paʁaˈtsɛlzʊs]; c. 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.

He was a pioneer in several aspects of the medical revolution of the Renaissance, emphasizing the value of observation in combination with received wisdom. He is credited as the "father of toxicology". Paracelsus also had a substantial influence as a prophet or diviner, his "Prognostications" being studied by Rosicrucians in the 17th century. Paracelsianism is the early modern medical movement inspired by the study of his works.

A sylph (also called sylphid) is an air spirit stemming from the 16th-century works of Paracelsus, who describes sylphs as (invisible) beings of the air, his elementals of air. A significant number of subsequent literary and occult works have been inspired by Paracelsus's concept: Robert Alfred Vaughan noted that "the wild but poetical fantasies" of Paracelsus had probably exercised a larger influence over his age and the subsequent one than is generally supposed, particularly on the Rosicrucians, but that through the 18th century they had become reduced to "machinery for the playwright" and "opera figurantes with wings of gauze and spangles".