Paracelsus explained

Oswald Crollius, Basilica Chymica (Frankfurt am Main, Gottfried Tambach), [ca. 1611]

Hermes Trismegistus was not only credited with philosophical writings but also with alchemical texts; he was regarded as one of the earliest authorities in this field. On this title page, he appears in the upper left corner, holding a fragment of one of his writings—the Tabula Smaragdina, or Emerald Tablet. Its most famous phrase, ‘As above, so below,’ refers to the connection between the macrocosm (the universe) and the microcosm (humanity).

The other five figures depicted on the title page are also prominent names in alchemy: Geber (presumably of Arabian origin), Roger Bacon (England), Paracelsus (Germany), Ramón Llull (Spain), and Morienus Mariyanus ar-Rahib (probably born in Rome). Morienus’ book was the first alchemical text to be translated from Arabic into Latin in Spain (1144), a task undertaken by Hugo of Santalla in Tarazona. Hugo also translated De secretis naturae et occultis rerum causis by Balinus, a work that, according to the version attributed to [pseudo-]Apollonius of Tyana, was derived from the books of Hermes Trismegistus. The oldest European version of the *Tabula Smaragdina* is found at the end of this book.

Crollius’ Basilica Chymica (c. 1563–1609) presents a philosophical exposition, supported by his own experiments, and discusses the proper use of chemical remedies, obtained through the illumination of the two sources of human knowledge: the light of grace and the light of nature. According to Paracelsian thought, these two lights are represented on the frontispiece by two triangles—one pointing upward (the light of grace) and the other pointing downward (the light of nature).

The Basilica Chymica was first published in Latin (Frankfurt, 1609), followed by translations into German (Frankfurt, 1623), French (Lyon, 1624), and English (London, 1657). Manuscript versions of the work also exist in Dutch (1615), Russian (1800), Arabic (Kitab Kimiya Basiliqa, 1700), and Spanish (1770), the latter translated by the renowned Toledo-based calligrapher Francisco Javier de Santiago Palomares.

The Basilica Chymica also includes a treatise on the inner signatures of things (De signaturis rerum internis), which demonstrates the correspondence between words and objects, signs and their meanings, and the intrinsic forces and virtues that govern the origin, development, and decay of things. In essence, the study of nature consists in deciphering and interpreting the signs it presents.

Undoubtedly, the most significant part of the work is its nearly one-hundred-page preface, in which, for the first time and in a contemporary language, the entire natural philosophy of Paracelsus is systematically explained, along with its impact on the progress and development of the sciences. Even in 1765, Diderot published a lengthy essay on Paracelsus and the Theosophists in Volume XVII of his Encyclopédie, which was derived from Crollius’ preface.