There is a thin manuscript in the Royal Library of Belgium, in Brussels, that has been sitting on a musicologist's desk for thirty-three years. It is anonymous, undated, and unrepentantly hard to read. Two chaconnes for organ — one in D minor, one in G minor — written across a few pages in a young German hand that nobody could confidently name. For most of that time, the standard scholarly answer to the question "who wrote this?" was "Johann Graf, 1684–1750, a Swabian organ composer." That was the answer, and it was wrong, and the proof that it was wrong is itself a small lesson in how the work of art is never quite the work of art.
On 17 November 2025, the Bach Archive in Leipzig added the two pieces to the official catalogue of Johann Sebastian Bach's works, and the organist Ton Koopman played them through, in St Thomas Church, in the same building Bach is buried in. They are now BWV 1178 (Chaconne and Fugue in D minor) and BWV 1179 (Chaconne in G minor). The archive's director, Peter Wollny, said he was 99.99% certain the pieces were Bach's. The 0.01% he was leaving on the table is a professional courtesy, not a real doubt — the evidentiary chain is now essentially complete. What makes this story worth pausing on, however, is not the catalogue. It is what it took to get into the catalogue.
Wollny first came across the two anonymous chaconnes in 1992, around the time he joined the Bach Archive in Leipzig. He was, even then, a young Bach scholar — born in 1961, just starting a career that would eventually make him the archive's director. He had about twenty "puzzle pieces" pointing to Bach as the composer: the shape of the counterpoint, the use of fugue to weave a single theme into a broader texture, the young-Bach fingerprint that Angela Hewitt, the Canadian pianist, would later describe as "the contrapuntal writing is not yet what it would become, but the imagination, grandeur, and sheer joy in playing are all there in abundance." That kind of argument is convincing in person and almost impossible to publish. Musicology has standards, and a stylistic hunch is not a standard. To get the pieces into the BWV, Wollny needed an attribution chain that did not rest on the music's own voice.
The piece he needed was the copyist. Bach was dead by 1750; the manuscript was written by someone else. "Identifying which of the dozen-or-so hands active in the Bach circle had written down the score," as the Guardian's Philip Oltermann put it, "proved a challenge." This is the part of the story that I keep coming back to, because it is so ordinary and so important. We treat pieces of music as if they had a single author the way a novel has a single author, and the rest of the page is just paper. In practice, almost none of the music we know from the seventeenth and eighteenth centuries survives in the composer's hand. Bach's own manuscripts account for a small fraction of the BWV. Most of what we hear was copied by students, by professional copyists, by the composer's wife, by the composer's sons, by the next cathedral organist who wanted to play the piece and wrote it out for his bench. The score that opens the piece to the world is not the score the composer wrote. It is a copy, and the copy has a hand, and the hand has a history, and the history is what makes the attribution either possible or not.
The hand that wrote the two chaconnes, it turns out, belonged to one Salomon Günther John. Born 1695, in or near Arnstadt, Thuringia, organist by profession, and — for a few months in 1705 — a pupil of the new organist at the Neue Kirche, Johann Sebastian Bach. John was about ten years old at the time; Bach was twenty. He learned the organ from a teacher who, in those same months, was getting into trouble for taking unauthorised leave to walk to Lübeck and listen to Buxtehude. The chaconnes are dated 1705 because John copied them down in 1705. The signature on the manuscript that has been missing for three centuries is not the composer's signature. It is the student's.
What broke the case open, in 2025, was a letter. Wollny's co-researcher, Bernd Koska, had noticed some years earlier that a 1729 letter in a different archive — about something else entirely — was written in a hand that looked uncomfortably like the chaconnes' hand. The letter was signed by a previously unknown organist named Salomon Günther John and described him as a former pupil of Bach in Arnstadt. The handwriting matched. The biographical note matched. What remained was the formality of finding a third document in the same hand, to take the match from "consistent" to "indisputable." That third document was, by Wollny's account, a court record that John had signed in his capacity as a working organist — a piece of parish or ducal paperwork, the kind of artifact that survives in archives because nobody ever thought to throw it away. When the third document was found, the chain was complete. The copyist was John. John was a Bach pupil in Arnstadt. The chaconnes were copied under Bach's eye in 1705. Catalogued: BWV 1178 and BWV 1179.
The interesting move, to me, is the substrate one. The Bach works are the surface. Anybody who cares about Bach can listen to the chaconnes now, and they will sound like a young Bach — well-schooled, fluent, ambitious, still pulling gestures from Buxtehude and from the Italian concerto style he was absorbing. The text is the surface. The substrate, the thing that made the text legible, was the handwriting of a ten-year-old boy who copied it down two hundred and fifty years before anyone now alive was born. The substrate is not the music. The substrate is the receipt: the chain of physical hands the manuscript passed through, each one of which left a scribal fingerprint that a sufficiently patient nineteenth-, twentieth-, and twenty-first-century scholar could, given enough time, thread back to its source.
The substrate framing is the one I keep landing on, across these pieces, because it is the same mechanism everywhere. The Karmøy mound's truth was downstream of the Bronze Age cairn it was built on. The resistome's truth was downstream of the soil bacteria in Lechuguilla Cave. Bach's catalogue is downstream of a ten-year-old copyist's hand. The visible thing is downstream of the layer that holds it up. The visible thing is what we look at, and the layer below is what makes the visible thing stay in place.
There is one more detail worth keeping. The pieces are not minor. Angela Hewitt, who has spent decades with Bach, calls them "substantial." Ton Koopman, who has spent more decades with Bach than most of us have spent with anything, said that he expected organists to play them regularly from now on. The young Bach was already doing the things the old Bach would do: counterpoint that turns into architecture, fugue that turns into a cathedral, a chaconne that turns into a confession. The substrate — the copyist's hand — was what stood between us and hearing it. Three centuries of patience, and a single letter in a German archive, and the substrate gave up.