In October 1802, in a quaint village near Vienna named Heiligenstadt, Ludwig van Beethoven took a moment to pen a letter to his brothers. At 31 years of age, he had been gradually losing his hearing for six years and realized by that autumn that his deafness would be permanent. In the letter, he articulated a particular kind of isolation — how he had started to evade social interactions because he could not endure the embarrassment of seeming to disregard others when he simply couldn’t hear their words. He expressed that it was solely his obligation to the uncomposed music that had prevented him from ending his life.
As the letter drew to a close, he made a specific appeal to his brothers. After his passing, he requested that they ask his doctor — Dr. Johann Adam Schmidt — to provide a detailed account of his ailment and to make this information public.
“So that, as far as possible, the world may reconcile with me after my demise,” he wrote.
He then folded the letter, concealed it within his writing desk, and kept its existence a secret for the following twenty-five years.
### The letter that was never sent
Beethoven outlived Dr. Schmidt by 18 years, as Schmidt passed away in 1809. Throughout his life, Beethoven continued to compose — despite his deafness, worsening digestive issues, recurrent bouts of jaundice, and a specific array of health problems that would plague him until the end. He also retained the Heiligenstadt letter in a secret section of his writing desk, unopened and unseen by anyone else.
He passed away in Vienna in March 1827, at the age of 56. The morning following his death, two associates sorting through his belongings stumbled upon the hidden compartment. Inside were several papers, including the letter he had penned 25 years prior in Heiligenstadt.
This document was published shortly thereafter. The specific request — for his physician to detail his illness and disseminate that information — could not be met, as Schmidt had been deceased for 18 years. Beethoven’s autopsy, conducted the day after his death, offered some insights but no conclusive diagnosis. The particular medical question the composer had wished to have clarified would remain, in the traditional biographical accounts, unresolved.
For 196 years, numerous doctors and biographers proposed hypotheses. Otosclerosis. Paget’s disease. Syphilis. Lead poisoning. Autoimmune disorders. Each theory supported some elements of the documented symptoms while contradicting others. None achieved unanimous agreement.
Then, in 2023, a team of scientists employed a method no one could have envisioned in 1802.
### Five locks of hair
The sequencing of Beethoven’s genome, published in the journal *Current Biology* in March 2023, took advantage of a peculiar aspect of nineteenth-century culture: the custom of preserving locks of hair from renowned individuals.
Beethoven’s hair had been widely preserved in the years surrounding his death and passed through private collections and museum archives. A team led by Tristan Begg at the University of Cambridge, in collaboration with Johannes Krause at the Max Planck Institute for Evolutionary Anthropology in Leipzig, collected eight locks purported to be Beethoven’s from various institutions and private owners across Europe and the United States.
Five of these eight locks, when genetically analyzed, were found to originate from the same European male. The remaining three belonged to entirely different individuals — prior DNA analyses of Beethoven had, inadvertently, sometimes involved hair from others.
The five verified locks provided the necessary material. Utilizing techniques developed in the last decade for extracting DNA from ancient human remains and adapting them to address the specific challenges posed by historical hair samples, the team sequenced Beethoven’s genome to 24-fold coverage from the best-preserved lock — a specimen known as the Stumpff Lock, which had been maintained in a private collection with particularly good records.
The resulting genome was nearly complete. It was the first genome of any historical figure sequenced from hair with this level of detail, enabling a genuinely direct evaluation of the biographical questions Beethoven himself had raised.
### What the DNA revealed
The revelations, when they emerged, were both partially fulfilling and somewhat peculiar.
The team discovered that Beethoven had a significant genetic tendency toward liver disease. Multiple risk variants across genes related to fat metabolism, alcohol processing, and liver inflammation were identified in his genome. This finding aligned with the two recorded episodes of jaundice he experienced in his last seven years, as well as the longstanding belief — upheld by biographers for two centuries — that liver failure played a role in his death. The genetic evidence rendered this assumption specific and testable.
More remarkably, hair samples from Beethoven’s final months contained DNA fragments from the hepatitis B virus. This was direct molecular evidence that Beethoven had been infected with a virus known to cause liver damage at some point in the year leading up to his death. Combined with his genetic predisposition and his well-