How the Pepys Diary Shorthand Was Finally Decoded

2026-09-09 · Yesterself

In 1819 the Master of Magdalene College, Cambridge, had a problem that was also an opportunity. On the shelves of the college's Pepys Library stood six neatly bound volumes covered in a small, dense script that nobody in the building could read. Everyone knew whose they were. Samuel Pepys had left his entire library to the college, arranged in his own bookcases, and it had stood there since 1724, when the bequest finally reached Cambridge after his nephew's death. Nobody knew what the six volumes said.

The year before, John Evelyn's diary had been published and had done well. Evelyn had been Pepys's friend and correspondent. If Evelyn's seventeenth century found readers, Pepys's might too — assuming anyone could get into it.

What happened next is one of the better stories in the history of private writing. It involves three years of a young man's life, a shorthand system that was never actually a secret, and a printed key to that system sitting a few yards from the person who most needed it.

The Pepys diary shorthand was a published system

The first thing to understand is that Pepys did not invent a cipher. He used Thomas Shelton's tachygraphy, a shorthand method Shelton had published decades earlier and which was widely taught and sold in seventeenth-century England. Clerks used it. Congregations used it to take down sermons. Pepys, a working naval administrator, had every practical reason to know it, and he used it for official notes as well as for the diary.

So the diary was not encrypted in any modern sense. It was written in a notation that thousands of Pepys's contemporaries could have picked up and read.

The system worked by replacing letters with short strokes and marks, then layering abbreviation on top: single symbols standing for whole common words, and vowels indicated less by their own characters than by where the following stroke was placed relative to the one before it. That last part is what makes it brutal to read cold. Position carries meaning. A mark set slightly high or slightly low is a different word, and a scribe writing fast for his own eyes only has no reason to be tidy about it.

Pepys added his own layer on top. Proper names he often wrote out in ordinary longhand. And in the passages about his sexual life he switched into a private mash of Spanish, French, Italian and invented words — shorthand carrying pidgin, so that even a reader fluent in Shelton would stumble.

His privacy, in other words, did not come from unbreakable secrecy. It came from friction, and from the reasonable assumption that nobody would care enough to push through it. That assumption held for about a century and a half.

Three years of a young man's life

The college hired John Smith, an undergraduate at St John's College, Cambridge, who was poor and needed the work. He was later ordained; most accounts of the diary call him the Reverend John Smith.

Smith started in 1819 and finished around 1822. The reports of his working habits are consistent and grim: very long days, month after month, sitting with the volumes and building the system back up from nothing. He had no teacher and no manual he knew of. He had to infer the rules from the evidence, the way you would attack an unknown script — guess at a frequent symbol, test the guess across hundreds of instances, discard it, guess again.

The finished transcript ran to thousands of pages across dozens of notebooks. Smith wrote out in longhand what Pepys had compressed into strokes, and in doing so he became the first person in a hundred and fifty years to know what was in the books.

The key was on a shelf in the same room

Here is the part everyone remembers, and by the usual account it is true: a copy of Shelton's own printed guide to the system was in the Pepys Library. Pepys had bought it. Pepys had bequeathed it along with everything else. It was in the collection Smith was working inside.

Nobody told him, because nobody knew to. The catalog was there, the book was there, and the connection between "the volumes we cannot read" and "the shorthand manual on shelf such-and-such" simply was not made by anyone in the room until later editors noticed it.

It is worth sitting with that for a second before turning it into a moral. The information required to read the diary in weeks instead of years was preserved perfectly, held in the same institution, under the same roof, by the same donor. What failed was not preservation. What failed was the pointer.

What the world got to read, and when

Smith's transcript went to the Master's kinsman, Richard Griffin, Lord Braybrooke, who edited it and published Memoirs of Samuel Pepys in 1825. It was a success, and it was heavily cut. Braybrooke printed a selection, trimmed for length and for decency, and readers took that selection for the diary.

Getting the rest out took another century and a half:

• In the 1870s Mynors Bright, a fellow of Magdalene, went back to the originals and re-transcribed, publishing a much fuller text.
• In the 1890s Henry B. Wheatley produced the edition most twentieth-century readers grew up on — fuller again, and still with passages left out as unprintable.
• Only with Robert Latham and William Matthews, whose eleven-volume edition appeared between 1970 and 1983, did the complete text arrive. Matthews was a scholar of the history of shorthand, which is precisely the expertise the job had needed all along.

If you want the diary itself rather than its decoding, start with the week it is most famous for: Pepys's entries on the Great Fire of London.

Writing that outlives its only fluent reader

Pepys is an unusually clean experiment. He kept something private for his lifetime, preserved it deliberately, and left behind exactly one problem: no living reader.

A few things follow that are worth borrowing, whatever you write in.

1. Obscurity is not privacy, but it is not nothing either. Shelton's system protected Pepys for 150 years, then stopped. If your writing must stay private past your interest in it, obscurity is the wrong tool. If you just want it not casually readable over your shoulder, it is a fine one.
2. Leave the key with the lock. Smith lost years to a missing pointer, not a missing document. A single plain page saying what the format is and how to open it is the cheapest insurance in the archive.
3. Prefer formats that do not need a specific reader. Plain text and open formats survive because anyone can open them. Anything requiring one company's app is one company's decision away from Shelton's strokes.
4. Decide, on purpose, whether there is a second reader. Pepys never had to answer this, because a bequest answered it for him. Most of us leave it to defaults.
5. Export on a schedule, not on an intuition. Whatever you write in, take a copy out yearly and open it somewhere else. That is the whole test.

This is history and file housekeeping, not legal advice. If the disposition of your papers genuinely matters — letters, journals, anything with money or family attached — talk to someone qualified about estates, and read whether personal papers are part of an estate first.

Yesterself sits deliberately on the strict side of this. Your writing is end-to-end encrypted and your identity is twelve words you hold, which means the server keeps ciphertext it cannot read and also means nobody can recover your words for you if you lose them. That is the honest trade. To balance it, export is free forever in open formats, on the free tier too, so the archive is never hostage to the app. And a steward can be handed one sealed capsule to deliver if you go quiet — a second reader you chose, rather than the one an institution appoints two centuries later.

Pepys got lucky. His pointer was only misplaced, not lost, and a poor undergraduate was willing to rebuild it by hand. Most private writing is not that fortunate. It is just quietly unreadable, and nobody ever knows what it said.

Common questions

What shorthand did Samuel Pepys use for his diary?

He used Thomas Shelton's tachygraphy, a shorthand system published decades before the diary and widely taught in seventeenth-century England. It was a public method, not a private cipher Pepys invented.

Was the Pepys diary written in a secret code?

Not really. The shorthand itself was learnable by anyone who owned Shelton's manual, though Pepys added obscurity by writing some sexual passages in a mixture of Spanish, French, Italian and made-up words on top of the shorthand.

Who decoded the Pepys diary shorthand?

John Smith, then an undergraduate at St John's College, Cambridge, transcribed the six volumes between roughly 1819 and 1822. His transcript was edited by Lord Braybrooke and published in 1825 as a heavily cut selection.

Was a key to the shorthand really in Pepys's own library?

By the usual account, yes. A copy of Shelton's printed guide to the system was among the books Pepys bequeathed to Magdalene College, on the shelves of the same library where Smith was working, and nobody made the connection at the time.

Is there a complete edition of the diary today?

Yes. The eleven-volume edition by Robert Latham and William Matthews, published between 1970 and 1983, is the first unabridged text; earlier editions by Braybrooke, Mynors Bright and Wheatley were all cut to some degree.