Lucas Jennis

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Lucas Jennis was a Frankfurt engraver and publisher active in the first decades of the seventeenth century, remembered chiefly for the illustrated alchemical books that came off his press. He belonged to the milieu of the Frankfurt book fair, then the clearing-house of European learning, and to the family of printers and engravers around Johann Theodor de Bry, whose plates set the visual standard for the alchemical emblem.

He came to the trade by inheritance and by marriage twice over. His father, Lucas Jennis the Elder, was a goldsmith, jeweler, and engraver who had fled religious persecution in Brussels and prospered in Frankfurt; engraving was the family craft before it became the son’s profession. The father died in 1606, and within a year the widow married Johann Israel de Bry, brother of Johann Theodor, so that the boy of about sixteen was absorbed into the most accomplished copperplate dynasty north of the Alps. The de Bry house had built its fortune on the great illustrated travel collections — the volumes of voyages to the Americas and the Indies whose finely cut plates were the benchmark of the German engraving trade. Jennis trained inside that workshop as stepnephew and apprentice of Johann Theodor de Bry, and married into the Frankfurt printing world as son-in-law of Sigmund Latomus. By the time he set up on his own account, the disciplines he commanded — the goldsmith’s burin, the engraver’s plate, the publisher’s reckoning of a fair-day market — were already braided together.

Little of his inner life is documented beyond the trade. He was born around 1590 and was issuing books under his own name by about 1616; the record of his activity thins out by about 1630. What survives is the catalog. He did not print every sheet himself in the modern sense; in the division of labor of the period the engraver-publisher supplied the capital, the copperplates, and the editorial selection, while the physical typesetting was let out to a printer’s shop. The imprints accordingly pair his name with the working presses he hired — Nicolaus Hoffmann, Hartmann Palthenius, and others in Frankfurt — so that a Jennis book typically reads as printed by one house at the expense of (sumptibus) Lucas Jennis. The formula is exact: the illustration and the money were his; the press was rented.

That arrangement was native to Frankfurt. Twice a year the city’s book fair drew printers, booksellers, and scholars from across the Empire and beyond it, and for the better part of two centuries it served as the single great exchange where the learned trade settled its accounts — where a publisher learned what would sell, where a Latin treatise found its translators, and where a folio printed in one principality reached readers in another. To publish at Frankfurt was to publish into a distribution network rather than a single city. A house that could supply finely engraved plates had a standing advantage there, because the alchemical and Hermetic books that were selling in the 1610s and 1620s were precisely the ones that could not be reduced to type. Jennis’s inheritance — copperplates, the burin, and a place inside the de Bry network — was exactly the capital the fair rewarded.

Engraving was not incidental to that capital; it was the costly heart of it. A copperplate was cut by hand, line by line, and could throw off only a limited number of clean impressions before the lines wore shallow and had to be recut or reworked; the plate was the expensive, reusable asset that a publisher guarded, leased, and passed from book to book. This is why the same figures recur across the Jennis catalog and across the wider de Bry corpus: a plate cut for one author’s treatise could be pressed into service for another’s, and a successful image was an investment to be amortized over several titles. The man who controlled the plates controlled the look of the art. When a reader in Prague or London opened an alchemical book and met the king and queen, or the green lion, the visual grammar that organized those figures had often been set in a goldsmith-engraver’s shop on the Rhine.

The migration of a workshop

The decisive shift in his career was not one he authored but one he inherited. Through the 1610s the most ambitious Hermetic and alchemical illustration in the Empire issued from Johann Theodor de Bry’s establishment at Oppenheim, a Palatine town on the Rhine south of Mainz, where the firm had moved to escape the Frankfurt guild restrictions and to settle within the Calvinist principality of Friedrich V. There the de Bry house, with the young Basel engraver who had married into it, produced the illustrated cosmologies of Robert Fludd and the emblematic alchemy of the physician and Imperial count Michael Maier — among them the celebrated emblem book of 1617 whose fifty plates wedded image, motto, epigram, and fugue. That whole program rested on a fragile political base. When the Palatine bid for the Bohemian crown collapsed at the Battle of White Mountain in 1620 and Oppenheim fell to Spanish arms, the matrix that had paid for the experiment was gone. The de Bry firm had already begun pulling back to Frankfurt; Johann Theodor died in 1623.

Jennis was the channel through which the work survived. He had been taking over most of the Maier imprints from 1618 onward — issuing them in Frankfurt, typically with Hoffmann or Palthenius at the press — so that when the Oppenheim infrastructure failed, the Hermetic catalog did not die with it but moved downriver into his shop. Around the same engravers, above all the Basel-trained hand whose plates had defined the Oppenheim look, the visual tradition continued in attenuated but unbroken form. The reader who bought a Maier or a Mylius from Jennis in the 1620s was buying the Oppenheim manner under a new imprint.

The catalog

The books that bear his name gathered the diffuse manuscript tradition of alchemy into printed compendia, paired with engraved plates whose images — the king and queen, the green lion, the hermaphrodite, the dragon devouring itself — did as much as the text to carry the discipline’s ideas. Beyond the Maier corpus he published the Opus Medico-Chymicum of the physician Johann Daniel Mylius, first printed in 1618 with copperplates by the de Bry house engraver; the emblem collections of Daniel Stolcius, whose Viridarium Chymicum of 1624 — a chemical pleasure-garden of allegorical figures with verse captions — was built on the model of Maier’s emblem book and assembled, at Jennis’s instigation, partly from plates already cut for Mylius; and the Dyas Chymica Tripartita of 1625, a German anthology edited by Johann Grasshoff that exemplified the house strategy — draw known authors to Frankfurt, render successful Latin treatises into German, and equip them with spectacular illustration. His shop is also the origin of one of the most reproduced of all alchemical images, the ouroboros — the serpent biting its own tail, the figure of the work that consumes and renews itself — cut for an emblem book on the philosophers’ stone in 1625.

The keystone is the Musaeum Hermeticum, which Jennis issued at Frankfurt in 1625. It was a compact anthology of relatively recent and relatively accessible alchemical writings — not the ancient, obscure authorities, but the younger school, gathered so that a reader could hold in one volume what otherwise lay scattered across separate tracts. Against the vast Latin storehouses of the age — the Theatrum Chemicum that Lazarus Zetzner had begun issuing from Strasbourg in 1602, and later Manget’s Bibliotheca Chemica Curiosa — the Musaeum was deliberately a working handbook rather than a stack of folios. The first edition of 1625 was printed in German and is now exceedingly rare. Half a century later the collection was recast and enlarged in Latin as the Musaeum Hermeticum Reformatum et Amplificatum, published at Frankfurt in 1678 with the addition of further treatises and reissued again in 1749. It was that Latin recension, descending from the volume Jennis first set in type, that A. E. Waite translated as The Hermetic Museum in 1893 and through which the compilation reached the modern reader.

Maker, not author

The distinction his work depended on, and which it is easy to lose, is between making a book and writing one. Jennis was not an alchemist setting down his own doctrine; he was a publisher and engraver who selected, printed, and illustrated the doctrines of others. That role mattered. Alchemical knowledge of this period traveled as much through pictures as through prose, and the men who cut the plates and assembled the volumes shaped what readers across Europe took the tradition to be. An emblem is not a decoration appended to a text; in the alchemical book it is a vehicle of doctrine in its own right, motto and image and verse converging on a single thought that prose could only circle. When Jennis chose which plates to recut, which treatises to gather under one cover, and which language to print them in, he was making editorial decisions about what the art was — decisions that reached more readers than any single author’s.

The images he circulated were not illustrations of a process so much as condensations of a doctrine. The king and queen joined in the chemical wedding figure the union of the two principles, the fixed and the volatile, the solar and the lunar, whose marriage is the work; the green lion is the corrosive solvent that swallows and reduces the metal; the hermaphrodite, the two-sexed body that results from their conjunction, is the reconciled opposites made one; and the dragon devouring its own tail — the ouroboros so closely associated with his shop — is the work that consumes itself to be reborn, the end folding back into the beginning. None of these required a caption to a reader trained in the tradition. They were a shorthand of transformation, legible across the language barriers of the fair, and the engraver who cut them was setting down the discipline’s grammar as surely as the author who wrote the prose.

The catalog sat at the meeting point of several currents. The years in which Jennis built his list were the years of the Rosicrucian ferment — the manifestos of the mid-1610s announcing an invisible brotherhood of reformers, and the flood of defenses and denunciations that followed — and the Maier volumes he took over, with their apologetics for the Fraternity, carried that enthusiasm into print. The iatrochemical works of Mylius descended from the medical reform of Paracelsus, who had insisted that the alchemist’s true gold was medicine. And the whole program drew its authority from Hermes Trismegistus, the legendary Egyptian master under whose name the art claimed its ancient descent — the name that gives the Musaeum Hermeticum its title. Jennis wrote none of this. He gave it a printed body and a face.

Scholarship and sources

The primary record of Jennis’s enterprise is the books themselves, nearly all of which are now public-domain by age and available in open digital repositories. The enlarged Latin Musaeum Hermeticum Reformatum et Amplificatum of 1678 — the recension Waite later Englished — is digitized in full by the Science History Institute in Philadelphia at digital.sciencehistory.org, which preserves its engraved plates at high resolution. The English descendant of that volume, A. E. Waite’s The Hermetic Museum of 1893, is held in the library’s alchemy collection. For the visual tradition in which Jennis worked, and for the migration of the Hermetic program from Oppenheim to Frankfurt, the Goethe-Universität Frankfurt’s documentary exhibition Bebilderung der Alchemie reconstructs the Frankfurt engraving trade — including Jennis’s 1622 publisher’s catalog — at merian-alchemie.ub.uni-frankfurt.de.

The standard biographical apparatus on Jennis as a maker, rather than as a theorist, is set within the wider study of the Frankfurt alchemical book trade: Joachim Telle’s work on alchemical printing and emblematics (2006) treats the Jennis imprints as a corpus, and the de Bry workshop and its engravers are the subject of the Hollstein research project on the dynasty. The most thorough recent reconstruction of the emblematic-alchemical book as an intermedial form — image, motto, epigram, and the doctrine they jointly carry — is the Brown / University of Virginia digital edition Furnace and Fugue, edited by Tara Nummedal and Donna Bilak, freely available at furnaceandfugue.org; its essays on the engravings situate the plates Jennis circulated within the precise workshop conventions from which they came. H. M. E. de Jong’s source-study of Maier’s emblem book (1969) remains the indispensable apparatus for reading the individual plates as carriers of textual tradition. Each of these treats Jennis in his proper register — not as the source of the doctrine but as the hand that fixed it in copper and put it on the fair-day stall.

An imprint outlives the man who signs it. The presses Jennis hired fell silent and his own name dropped from the colophons by 1630, but the volumes went on doing his work without him: bound, sold at successive Frankfurt fairs, copied plate-for-plate into later compendia, recast in Latin in 1678, Englished in 1893, and still consulted as the standard form in which a whole school of the art reached print. The Musaeum Hermeticum he assembled became the entry through which readers met that school, and it carried his selection — these treatises and not others, these plates and not others — long after the shop that issued it had closed its books.

→ In the library: The Hermetic Museum (Waite, 1893) — English of the work Jennis published

→ Related: Lazarus Zetzner · Hermes Trismegistus · Modern Hermeticism Hermetic Revival · Alchemy · Emblematics · Rosicrucianism · Robert Fludd · Paracelsus