Historical eventSeptember 271822

Lettre à M. Dacier

In a letter to the Académie des Inscriptions et Belles-Lettres in Paris, Jean-François Champollion announced his initial successes in deciphering Egyptian hieroglyphs on the Rosetta Stone (pictured).

Everything on September 27Original source

In context

When
Friday, September 27 1822204 years ago
Category
Historical eventA dated happening — a battle, treaty, launch, discovery, disaster or decision — recorded on this calendar day.
Era
19th century · 1820s
Recorded from
Wikipedia “On this day” feed

Russia, Greece and some other countries used the Julian calendar into the early 20th century, so local records may show a date up to 13 days earlier.

At a glance

Dates: From 1822.

What happened

In a letter to the Académie des Inscriptions et Belles-Lettres in Paris, Jean-François Champollion announced his initial successes in deciphering Egyptian hieroglyphs on the Rosetta Stone (pictured).

September 27 through the years

Other entries on the same calendar day, in order.

  1. 1822Lettre à M. Dacier
  2. 2001Zug massacre
  3. 2003SMART-1
  4. 2007Dawn (spacecraft)
  5. 2008Zhai Zhigang
  6. 2012Minneapolis firm shooting
  7. 2014Mount Ontake
  8. 20142014 Mount Ontake eruption
  9. 2019September 2019 climate strikes
  10. 2020Second Nagorno-Karabakh War
  11. 2024Hurricane Helene

Also in 1822

  • June 14Royal Astronomical SocietyIn a paper presented to the Royal Astronomical Society, English mathematician Charles Babbage proposed a difference engine (pictured), an…
  • December 9French Academy of SciencesIn a memoir read to the French Academy of Sciences, Augustin-Jean Fresnel coined the terms linear, circular, and elliptical polarization,…
  • September 7Pedro I of BrazilPedro I declared the independence of Brazil from Portugal, establishing the Empire of Brazil (flag pictured).
  • March 30East FloridaThe United States merged East Florida and West Florida to create the Florida Territory.
  • November 9USS Alligator (1820)USS Alligator engaged three pirate schooners off the coast of Cuba in one of the West Indies anti-piracy operations of the United States.
  • December 1Pedro I of BrazilPedro I was crowned the first emperor of Brazil, seven weeks after his reign began on his 24th birthday.
  • June 6Alexis St. MartinAlexis St. Martin, a Canadian voyageur, was accidentally shot in the stomach; medical investigations of his injury led to a greater under…
  • May 26Grue Church fireThe deadliest fire in Norwegian history occurred at a church in Grue, killing at least 113 people.

Everything we record for 1822 →

Sources

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“Lettre à M. Dacier”, What's On This Date, https://whatsonthisdate.com/app/event/lettre-m-dacier-1822-september-27, accessed October 28, 2026.

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Questions about this entry

When did Lettre à M. Dacier happen?

September 27 1822 — 204 years ago, on a Friday.

Where does this text come from?

Wikipedia “On this day” feed. Summaries are short adaptations that link back to the source, not reprints.

How do I cite this page?

Use the ready-made citation near the sources at the bottom of the page, and follow the source link to cite the underlying record as well.

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