Steganographia: Trithemius's Spirit Book Was a Cipher

What the Steganographia is

The title is a coined word from Greek: steganós, covered, and gráphein, to write. Covered writing. Trithemius coined the word, and our modern term steganography, the art of hiding a message inside something harmless, comes straight from this book title.

• Author: Johannes Trithemius (1462–1516), Benedictine, abbot of Sponheim near Bad Kreuznach, from 1506 abbot of St. Jakob in Würzburg
• Written: around 1499/1500, unfinished
• Structure: three books
• First printed: Frankfurt am Main, 1606, ninety years after the author's death
• Subject, according to the title: the art of communicating your will to people far away through hidden writing

On the outside, the work promises to send messages across any distance with the help of spirits, with no messenger and no letter. On the inside, it is a textbook of encryption.

The abbot of Sponheim

Trithemius, born in Trittenheim on the Moselle, became abbot of a run-down monastery in the Hunsrück hills at twenty-one and turned it into one of the most famous libraries north of the Alps: just under fifty volumes grew to around two thousand. Scholars and princes traveled to see it. He wrote chronicles, rules for monks, a praise of scribes against the printing press, and he was passionately interested in what he called natural magic.

Among his visitors in the winter of 1509/10 was the young Heinrich Cornelius Agrippa, who soon afterward dedicated the first version of his Occult Philosophy to him. Where that road led is traced in our guide to Agrippa's Three Books of Occult Philosophy.

Books I and II: spirits that are really letters

The first book assigns thirty-one spirit princes to the points of the compass, each with dukes and servants, each with an invocation of its own. The second book distributes spirits across the hours of day and night. If you want to send a secret message, the instructions say, you write a harmless letter, call on the responsible spirit and entrust it with the real message; the recipient summons it again with the counter-formula.

The trick: the invocations themselves are the instructions. Read only certain letters of certain words and you'll find, in Latin or German, how the accompanying letter is to be deciphered. The invocation of the spirit Padiel begins like this:

Word of the formula	Rule	What remains
padiel	filler word, skip	–
a p o r s y	every second letter	pry
mesarpon	filler word, skip	–
o m e u a s	every second letter	mus
peludyn	filler word, skip	–
m a l p r e a x o	every second letter	apex

Result: prymus apex, Latin for "the first letter." The spirit formula tells the initiated reader which rule to use for reading the cover letter.

What sounds like the language of demons is packaging. And that was no secret, at the latest after the first printing: the Frankfurt edition of 1606 came with a key, the Clavis Steganographiae, which lays out the methods of the first two books step by step.

Book III: the riddle that remained

The third book is different. It breaks off mid-thought, contains no more invocations, and instead offers tables full of numbers, ordered by the seven planets and their angels, from Oriphiel for Saturn to Gabriel for the Moon. The text speaks of images to be made at particular hours and of messages that reach their target within twenty-four hours, without word, writing or messenger.

For this book, the Clavis gave no key. And so the learned world split for centuries. Some saw cryptography in the first two books and genuine astral magic in the third, proof that Trithemius was a magician after all. Respected Renaissance scholars still followed this reading in the 20th century. Others suspected a cipher here too but could not produce one. A lawyer from Worms named Wolfgang Ernst Heidel claimed in 1676 that he had found the solution and published it, encrypted in turn.

The solution after five hundred years

In the 1990s the third book was cracked twice, independently. The German literature scholar Thomas Ernst presented his solution in a long German-language study that appeared in the journal Daphnis in 1996. The mathematician Jim Reeds of AT&T Labs, without knowing Ernst's work, reached the same result and published it in 1998 in the journal Cryptologia.

Both showed that the numbers in the planetary tables are letters. Behind them is a fairly simple substitution method using a backward-running alphabet in several blocks of numbers. The plaintexts are disarmingly mundane: a Latin mnemonic verse that contains almost the entire alphabet, the opening of a psalm, and a German sentence saying that the bearer of a letter is a rogue and a thief. A teacher's practice sentences, not messages from angels.

That settled the old dispute at its core: all three books of the Steganographia contain cryptography. What is not settled, and cannot be settled from the text alone, is whether Trithemius saw the magical shell purely as camouflage.

Book	Surface	Underneath	Decoded by
I	31 spirits of the air for the compass points	Letter selection inside filler words	Clavis, printed 1606
II	Spirits of the hours of day and night	Substitution alphabets	Clavis, printed 1606
III	Planetary angels, number tables, image magic	Numbers standing for letters	Ernst 1996, Reeds 1998

The scandal: Bostius, Bovelles and the Index

That the book harmed its author came down to two accidents. In 1499 Trithemius wrote an enthusiastic letter about his new work and its unheard-of possibilities to a Carmelite friend in Ghent, Arnold Bostius. Bostius died before the letter arrived; the prior opened it, and copies made the rounds. A few years later the French scholar Charles de Bovelles visited Sponheim, leafed through the manuscript, read the spirit names and was horrified. In a letter that was soon printed, he called the abbot a conjurer of demons.

Trithemius defended himself until the end of his life: he was a Christian, a monk and a priest, and his art was natural and permitted. He kept the Steganographia back. It circulated only in handwritten copies; the English scholar John Dee copied one out in ten days in Antwerp in 1563 and proudly reported the find to London. In 1609, three years after the first printing, Rome put the book on the Index of Forbidden Books. It stayed there until 1900.

Why disguise a cipher manual as a book of magic?

Scholars name several motives, and they don't exclude one another:

• Protecting the knowledge. Trithemius himself writes that the art must not fall into unworthy hands. Anyone who recoils from demons stops reading.
• A learned game. A book about hiding that is itself hidden suits the humanists' taste for riddles and false bottoms.
• A worldview. For Trithemius, number, language, star and angel were parts of the same order. In his treatise on the seven planetary spirits that take turns ruling the ages of the world, he takes the angels quite seriously.

The sober sister of the Steganographia shows where the journey led: in 1508 Trithemius completed the Polygraphia, printed in 1518 and thus the first printed book on cryptography ever. It contains the square letter table from which the Vigenère cipher later developed, and a method that replaces each letter with a pious Latin word so that the secret message reads like a prayer.

Afterlife in the grimoires

The magicians took the book at its word anyway. The spirit princes of the first book, Pamersiel, Padiel, Camuel, Aseliel and the rest, migrated in the 17th century, ranks and compass points included, into the Theurgia-Goetia, the second part of the Lemegeton. There, a cryptographer's filler names became beings with seals and hours of service. How that collection came together is told in our guide to the Ars Goetia and where its 72 demons came from.

John Dee, who had wanted the copy so badly, developed his own system of angelic communication with Edward Kelley two decades later, with tables, letter squares and a language of its own. The family resemblance is hard to miss; more on that in our article on the Enochian language of John Dee.

Hiding and condensing: what magic and cipher have in common

You can read the story as disenchantment: where spirits stood, there are letters. I prefer to read it as a hint at how close the two lie together. A cipher takes a sentence and makes it unreadable to everyone except whoever holds the key. A sigil takes a sentence and condenses it into a sign that means something only to the person who made it. Both arts live on meaning taking a form that both preserves and conceals it. If you want to try the second one, our guide on how to make a sigil walks you through it.

Quiz: how would you read the Steganographia?

Voices from practice

In forums on the history of cryptography, the Steganographia is a favorite teaching example: people who count out the Padiel formula themselves for the first time regularly describe the same moment of amazement when gibberish turns into a Latin word. Among practitioners of ceremonial magic you meet two attitudes. Some say the decryption finished the book as a magical source. Others keep working with the spirit lists and point out that names gain a life of their own through centuries of use, however they came into being. And librarians of old collections report that hardly any volume is requested so often with the question of whether it's dangerous.

What we don't promise

We don't promise that this book lets you summon spirits or transmit thoughts; the formulas are demonstrably cipher texts. Nor do we claim to have the last word on Trithemius's own convictions. Whether he believed in working angel magic alongside the cryptography is an open question among specialists. And we advise against using the methods of the Steganographia for real secrets: they are historically delightful but, by today's standards, breakable in minutes.

Practically: what to do with it

• Read the original. The Frankfurt edition of 1606 has been digitized by several libraries and is freely viewable; the Twilit Grotto (esotericarchives.com) offers a Latin transcription with a partial English translation.
• Count it out yourself. Take the Padiel formula from the table above and follow the rule. Ten minutes, and you'll understand the principle better than from any description.
• Build your own formula. Write a short word, spread its letters over every second position of made-up names, and put filler words in between. That's how it feels to do what Trithemius did.
• Keep the layers apart. What the book says, what the Clavis explains, what Ernst and Reeds proved and what later grimoires made of it are four different things.
• Move on to the Polygraphia if the technique interests you. There you'll find the same art without the mask.

Frequently asked questions

What is the Steganographia?

A work in three books written around 1500 by the abbot Johannes Trithemius. It presents itself as a guide to summoning spirits but teaches methods of secret communication.

Is the Steganographia a book of magic?

In form yes, in content no. The invocations and number tables of all three books are demonstrably ciphers. Later grimoires did, however, take over the spirit names as real lists of spirits.

Who decoded Book III of the Steganographia?

Thomas Ernst, whose solution appeared in the journal Daphnis in 1996, and independently Jim Reeds, who published it in Cryptologia in 1998.

Why was the Steganographia banned?

Because of its spirit names and invocations it was considered demon magic. Rome placed it on the Index of Forbidden Books in 1609 and removed it only in 1900.

What is the difference between the Steganographia and the Polygraphia?

The Steganographia hides its methods in magical language and stayed unprinted during Trithemius's lifetime. The Polygraphia, printed in 1518, treats cryptography openly and is considered the first printed book in the field.

Where does the word steganography come from?

From the title of this book. Trithemius formed it from the Greek words for covered and writing.

Sources and further reading

• Johannes Trithemius: Steganographia, with Clavis, Frankfurt am Main 1606.
• Thomas Ernst: study of the key to the third book of the Steganographia, Daphnis 25 (1996).
• Jim Reeds: "Solved: The Ciphers in Book III of Trithemius's Steganographia," Cryptologia 22 (1998).
• Klaus Arnold: Johannes Trithemius (1462–1516), 2nd edition, Würzburg 1991.
• Noel L. Brann: Trithemius and Magical Theology, Albany 1999.
• On Desire Diaries: Agrippa's Occult Philosophy · Ars Goetia · Enochian language · Picatrix

Historical facts are cited above; the magical claims attached to the book are not proven. Last updated: October 26, 2026.