Isaac Casaubon

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Sometime in the months before midsummer 1614, in a London house lent to him by Bishop John Overall, a Geneva-born philologist worked through the opening pages of a Catholic cardinal’s church history with the same instruments he had turned on Strabo, Athenaeus, and Polybius — a reader’s pen, a printed Greek text, and an ear trained to hear which century a sentence belonged to. The pages concerned the pagan witnesses who, the cardinal held, had foretold Christ. One of those witnesses was Hermes Trismegistus. Isaac Casaubon read the Greek attributed to him, weighed its vocabulary against the documented history of the language, and concluded that the most ancient theologian of the gentiles had written long after the apostles. He died on 1 July 1614, weeks after the book was printed, and was buried in the south transept of Westminster Abbey. The roughly eighteen folio pages in which he made that argument have since carried more weight in the history of the Hermetic writings than almost any other stretch of seventeenth-century scholarship.

A Huguenot scholar’s life

Casaubon was born in Geneva on 18 February 1559, the son of Arnaud Casaubon, a Gascon Huguenot pastor, and Jeanne Rousseau, refugees who had fled persecution in the French southwest. The family returned to France after the Edict of Saint-Germain and settled at Crest in the Dauphiné, where the boy grew up amid the violence of the Wars of Religion. He received almost no formal schooling before nineteen; his first lesson in Greek — parsing a speech of Isocrates — was given by his father in a mountain cave where the family had hidden after the St Bartholomew’s Day massacre of August 1572. The detail is not legend but the record of a Calvinist childhood shaped by flight, and it marks the temper of the man: the philology he would perfect was learned under the pressure of confession from the start.

He entered the Academy of Geneva in 1578, studied under the Cretan Hellenist Francis Portus, and on Portus’s death succeeded him in the chair of Greek at twenty-two, holding it from 1582 to 1596. In 1586 he married Florence Estienne, daughter of the scholar-printer Henri Estienne, binding himself into the most distinguished Hellenist press of the Reformed world. From Geneva he moved to Montpellier (1596–1599) and then to Paris, where Henri IV made him sous-bibliothécaire of the royal library and used him as one of the Protestant referees at the 1600 Conference of Fontainebleau. The assassination of Henri IV in May 1610 ended his French employment within months. By October 1610 Casaubon was in England, drawn there by James I — the most learned theologian to sit on the English throne — with a royal pension of £300 and a prebend at Canterbury Cathedral. His last years show a steady drift from strict Geneva Calvinism toward the patristic, conciliar temper of Lancelot Andrewes and the early Anglican school, a drift that sharpened his appetite for prying the early Christian centuries loose from Catholic reconstructions of them.

His reputation rested on a body of editions that became models of method. Casaubon edited Diogenes Laertius (1583), Strabo’s Geography (1587), Theophrastus’s Characters (1592), Suetonius (1595), Athenaeus’s Deipnosophistae (with the celebrated Animadversiones, 1597–1600), the Historia Augusta (1603), Persius (1605), and Polybius (1609). The technique is consistent across all of them: collation of manuscripts, lexical and stylistic dating, and exhaustive harvesting of testimonia from later authors to fix a text in time and milieu. His closest scholarly companion was Joseph Justus Scaliger (1540–1609), the supreme chronologist of the age, whose De emendatione temporum (1583) had built the framework of comparative dating that gave Casaubon’s later arguments their technical bite. The two corresponded for fifteen years and never met.

The royal commission against Baronio

The 1614 Hermetica argument did not begin as an inquiry into Hermes. It began as a commission. James I asked Casaubon to refute the Annales Ecclesiastici of Cardinal Cesare Baronio (1538–1607), the Vatican Librarian and Oratorian whose twelve folio volumes (Rome, 1588–1607) were the great Catholic counter-history written against the Lutheran Magdeburg Centuries. To answer Baronio was, for an English Protestant crown, a confessional imperative. Casaubon’s reply was titled De rebus sacris et ecclesiasticis exercitationes XVI: ad Cardinalis Baronii Prolegomena in Annales, printed in London in folio by the King’s Printer John Bill at the Norton press, with the king’s privilege and a dedication to James. The plan was sixteen exercitationes against Baronio’s first volume alone, with comparable instalments to follow against the other eleven. Casaubon died with only the first volume completed, having reached Baronio’s entries for the year 34 of the Common Era.

The argument over Hermes sits inside the first Exercitatio, conventionally cited as Exercitatio I, section 10, occupying roughly pages 70 to 87 of the 1614 folio. Baronio’s opening pages had cited Hermes Trismegistus among the pagans who testified to Christian truth in advance — a sage held to be contemporary with, or older than, Moses, whose writings looked like a second testament of natural revelation. To dismantle Baronio’s Hermes, Casaubon had to redate the whole Hermetic corpus; and to redate it, he deployed the full apparatus of internal-evidence philology. The polemical occasion was not external to the argument but constitutive of it — a fact long obscured by the way the excursus came to be read as a free-standing landmark in the history of criticism.

The world the argument overturned

To grasp the weight of what Casaubon did, one must enter the world he was reading against — a world in which the antiquity of Hermes was not a credulous fancy but a reasoned scholarly position. When Marsilio Ficino completed his Latin translation of the Hermetica in 1463 — set in motion when Cosimo de’ Medici, sensing death near, had him interrupt his Plato to render the Greek treatises first — he received them as the oldest theology of all. In the Argumentum prefacing his Pimander he laid out the genealogy that defined the whole Renaissance project: a chain of ancient sages — Hermes Trismegistus, Orpheus, Pythagoras, Plato — through whom a single divine wisdom had descended, with Hermes at or near its head, an Egyptian roughly contemporary with Moses who had foreseen the Trinity and the Word. This was the prisca theologia, the ancient theology, and on it rested the immense authority the texts enjoyed: their resemblance to Christian and Platonic doctrine looked like prophecy rather than borrowing. The dating gave the writings their power. To read the Asclepius or the Poimandres in 1500 was to read, it was believed, a gentile revelation older than the Hebrew prophets and providentially harmonized with the gospel.

The building did not stop with Ficino. Giovanni Pico della Mirandola wove Hermes into a still wider synthesis with Cabbala and Platonism; the Asclepius furnished his most famous line on the dignity of man. The corpus was enlarged when later hands translated treatises Ficino had not seen, and Francesco Patrizi appended the full Greek and Latin Hermetica, the Chaldean Oracles, and more to his Nova de Universis Philosophia (1591), proposing that this Platonic-Hermetic synthesis replace Aristotle in the Catholic universities. The work was placed on the Index donec corrigatur. Giordano Bruno drew on the Asclepius throughout his dialogues and built from Hermes the most radical attempt of the age to found a renewed pagan philosophical religion, an attempt that ended at the stake in 1600. Robert Fludd and, in his own register, the Jesuit Athanasius Kircher carried the figure into the seventeenth century. This was the edifice — Ficino’s, Pico’s, Patrizi’s, Bruno’s, Fludd’s — whose chronological foundation Casaubon examined in eighteen pages, and the Renaissance valuation of Hermes was the intellectual atmosphere of an entire learned Europe.

The philological case

Casaubon worked from Adrien Turnèbe’s 1554 Paris Greek edition of the corpus, annotating it in the margins, alongside Ficino’s Latin and François de Foix-Candale’s Greek-Latin Bordeaux edition of 1574. His argument is cumulative: no single observation is decisive in isolation, but the convergence is overwhelming. Several independent strands meet.

The Greek itself is late. The vocabulary, sentence structure, and rhetorical idiom of the Hermetica are not those of an archaic Egyptian text or of Plato’s contemporaries but of Hellenistic and Imperial Greek — closer, as Casaubon put it, to the manner of Pseudo-Dionysius the Areopagite, a Christian pseudepigraph already exposed by Lorenzo Valla, than to anything primordial. The texts carry technical Platonist and Stoic vocabulary — the Demiurge, the hypostatized Logos, the levels of being — that belongs to schools long after Moses. They echo the Greek of the Septuagint, including the creation language of Genesis, which a pre-Mosaic Egyptian could not have known since that translation was made in Alexandria centuries later. They are silent in the entire pre-Christian record: not Plato, not Aristotle, not Cicero, not Plutarch mentions them, and the first datable citations come only with Lactantius in the early fourth century, then Augustine and Cyril of Alexandria — exactly when Christian apologetics had motive to summon a pagan witness. And they contain phrasings that track Christian doctrine too closely for coincidence: against a passage in the fourth treatise, the Krater or Cup where the soul is immersed in nous, Casaubon wrote in his margin that it alludes to baptism. Elsewhere, his pen drove the contradiction to its breaking point: if this is true and the author wrote before Moses, then God revealed his mysteries through this man and not through Moses — a conclusion no Christian could accept.

From these strands Casaubon concluded that the corpus, with the Poimandres and the Latin Asclepius foremost among its treatises, was the work of Greek-speaking authors of the post-apostolic period, broadly the second and third centuries CE — a late-antique writer assuming the mask of an ancient sage as a dolus bonus, a pious deceit meant to lend revealed truth the look of independent pagan confirmation. The method had precedent: Valla had demolished the Donation of Constantine the same way, by hearing the wrong century in its Latin. What was new was the systematic application of linguistic stratification — diction, citation horizon, doctrinal content, intertextual borrowing — to fix the composition window of an entire ancient text. In Anthony Grafton’s reconstruction this stands near the beginning of the long line that runs through Spinoza and Richard Simon to the historical criticism of the nineteenth century; Grafton stresses equally that Casaubon’s tools were largely ancient, recycled from patristic and Porphyrian source-criticism, and that the same skeptical edge he brought to pagan pseudepigrapha he held back from the texts his own confession required.

What Casaubon did not claim

The shorthand that Casaubon killed the Hermetica misreports him. His complaint was historical, not aesthetic: he never called the writings worthless, and he went on reading Pseudo-Dionysius and Iamblichus critically rather than discarding them. Following Augustine and Lactantius, he allowed that an ancient figure named Hermes or Thoth might have existed, and denied only that the surviving Greek treatises were that figure’s composition. He even left room — a nuance his readers dropped almost at once — for an older substratum of Egyptian theological material beneath the late Greek redaction. His targets were Baronio’s chronology and the prisca theologia genealogy that turned Hermes into a witness for Catholic doctrine, not Hermetic philosophy as such. He relocated the texts in time; he did not pronounce on their worth.

Measured against later scholarship his dating has held, while his texture has been revised. The surviving philosophical Hermetica are now placed in Hellenistic-Roman Egypt of the first three centuries CE, just as Casaubon argued. But he flattened a stratified corpus into a single late date, and — working before Champollion had unlocked the hieroglyphs — he underestimated how much genuine Egyptian priestly thought the Greek encodes. The recovery of three Hermetic texts among the Coptic codices found near Nag Hammadi in 1945 confirmed his chronology while disclosing a lived religious practice his forgery-and-fabrication frame could not hold. The verdict that has structured all serious reading since was drawn by Cudworth: the date of the Greek redaction is not the date of the doctrine it carries. Casaubon was right about when, and only partly right about what.

The afterlife of an argument

In the Protestant philological networks of Leiden, Oxford, and London the redating was settled doctrine within a generation. Yet the texts themselves did not vanish with their antiquity. The most consequential reply came from the Cambridge Platonists: Ralph Cudworth, in The True Intellectual System of the Universe (1678), conceded Casaubon’s philology for a minority of the treatises while arguing that the rest preserved a genuinely older Egyptian-Greek wisdom redacted late — the distinction between a terminus ad quem of the surviving text and a terminus a quo of its content that frames responsible Hermetic scholarship to this day. Henry More absorbed Hermetic motifs into the same Cambridge synthesis. Athanasius Kircher, in his Oedipus Aegyptiacus (1652–54), engaged the philology with care yet preserved Hermes as a real Egyptian sage whose oral wisdom had merely been rewritten in Greek — not obscurantism, but a deliberate rescue of the figure from the verdict on the books.

The spiritual reception ran on almost untouched by the chronology. In the very months that Casaubon’s Exercitationes left John Bill’s London shop, the Rosicrucian Fama Fraternitatis (1614) was being printed in Kassel, treating Hermetic antiquity as unproblematic; the Confessio followed in 1615. Rosicrucian and alchemical writers, the theosophical undergrounds, and later Theosophy carried the older dating forward into the nineteenth century — Helena Blavatsky read the Hermetica as preserving genuine pre-Mosaic wisdom and declined to meet the philological argument on its own ground, holding that academic method is constitutionally unable to perceive an esoteric sense. The historian’s puzzle is real: a dating effectively closed in the seminar room by 1700 remained open in the lodge and the laboratory for two centuries more. What endured was not the antiquity Casaubon took away but the texts themselves, which proved more durable than the age once claimed for them.

Scholarship and editions

The indispensable primary document is Casaubon’s own folio, De rebus sacris et ecclesiasticis exercitationes XVI (London: John Bill, 1614), with the Hermetica argument at Exercitatio I.10, pp. 70–87; it is public domain and digitized (Internet Archive identifier isaacicasauboni00unkngoog; Google Books sojXMoVjCgIC). No complete English translation of that section exists, a standing gap in the literature. The standard English-language biography remains Mark Pattison’s Isaac Casaubon, 1559–1614 (London: Longmans, Green, 1875; 2nd ed., Oxford: Clarendon, 1892), with the Hermetica discussion in chapter 6 (Internet Archive isaaccasaubon15500pattuoft). G. R. S. Mead summarized and contested Casaubon’s verdict in Thrice-Greatest Hermes, vol. I (1906), ch. II. The transitional document toward the modern consensus is Richard Reitzenstein’s Poimandres: Studien zur griechisch-ägyptischen und frühchristlichen Literatur (Leipzig: Teubner, 1904), which relocated the corpus in Hellenistic-Egyptian milieus while reviving Cudworth’s intuition of an older substrate (Internet Archive poimandresstudie00reituoft).

The modern scholarship that established and qualified the picture is in copyright and cited here for reference. The foundational study of Casaubon’s argument is Anthony Grafton, “Protestant versus Prophet: Isaac Casaubon on Hermes Trismegistus,” Journal of the Warburg and Courtauld Institutes 46 (1983): 78–93 (doi.org/10.2307/751115), expanded as chapter 5 of his Defenders of the Text (Harvard, 1991). Frances Yates cast the redating as the watershed dividing the Renaissance world from the modern one in Giordano Bruno and the Hermetic Tradition (University of Chicago Press, 1964), whose ch. XXI is titled “After Hermes Trismegistus was Dated.” That rupture thesis has since been qualified: Martin Mulsow’s Das Ende des Hermetismus (Tübingen: Mohr Siebeck, 2002) documents that the philological doubting of Hermes was under way for almost half a century before 1614, from Gilbert Genebrard’s Chronographia (1567) onward, making Casaubon the culmination rather than the inauguration of the argument; and Wouter Hanegraaff, in Esotericism and the Academy: Rejected Knowledge in Western Culture (Cambridge University Press, 2012), reframes Casaubon as one instrument among several by which a modern category of rejected knowledge was constructed. For the texts themselves, the standard English edition is Brian Copenhaver’s Hermetica (Cambridge University Press, 1992), whose introduction synthesizes the dating debate, and Garth Fowden’s The Egyptian Hermes (Princeton University Press, 1986/1993) develops the recovery of the corpus’s Greco-Egyptian temple milieu.

Casaubon’s eighteen pages remain an unusual artefact: a confessionally driven polemic that established a chronological fact still standing four centuries later. They show how decisive philology can be motivated by sectarian aim and yet yield a result that outlives the quarrel — and they mark the distance between an intellectual settlement and a cultural one, since the antiquity Casaubon retired from the seminar lived on for generations in the workshop, the lodge, and the visionary tract. The texts Ficino translated in 1463 are not what he took them to be; they are also not nothing, and what they actually are has been the work of the four centuries since this Huguenot philologist, dying in a borrowed London house, finished reading them.

→ In the library: The Corpus Hermeticum (Mead) — I. Poemandres · The Corpus Hermeticum (Mead) — V. The Cup or Monad · Thrice-Greatest Hermes, Vol. I — Prolegomena (1906)

→ Related: Hermes Trismegistus · Corpus Hermeticum · Prisca Theologia · Renaissance Hermetism · Marsilio Ficino · Neoplatonism · Cambridge Platonism · Gnosis · James I · Frances Yates · Francesco Patrizi · Giordano Bruno · Giovanni Pico Della Mirandola · Henry More