| 1799–1825 | [maths] | The French mathematician and physicist Pierre-Simon Laplace publishes the five-volume Traité de mécanique céleste/Celestial Mechanics, which applies calculus to the motions of celestial bodies and Isaac Newton's theories of the Solar System to show how its stability is implicit in the law of gravitation. |
| 1800–1850 | USA [consumer products] | A revolution in retail and wholesale trade occurs: specialization transforms the urban retail market, replacing the general store with individual stores for hardware, groceries, dry goods, furnishing, books, tobacco, and so on. Cash-only sales policies are instituted around 1806. |
| 1808 | Germany [orchestral music] | The German composer Ludwig van Beethoven completes his Symphonies No. 5 in C minor (Opus 67) and No. 6 in F, the Pastoral (Opus 68) and his Cello Sonata in A major (Opus 69). |
| 1808 | Germany [painting] | The German artist Caspar David Friedrich paints The Cross on the Mountains and becomes one of the leading exponents of German Romanticism. |
| 1808 | France [painting] | The French artist Jean-Auguste-Dominique Ingres paints The Valpinçon Bather and Oedipus and the Sphinx. |
| 1808 | Germany [philosophy] | The German philosopher Johann Gottlieb Fichte publishes Reden an die deutsche Nation/Addresses to the German Nation. This work plays an important role in the development of German nationalism. |
| 1808 | Germany [plays] | The comedy Der zerbrochene Krug/The Broken Jug by the German dramatist Heinrich Wilhelm von Kleist is first performed, produced by Johann Wolfgang von Goethe, in Weimar, Germany. |
| 2 February 1808 | France, Papal States [political events] | A French force under General Sextius Miollis occupies Rome after Pope Pius VII refuses to recognize the Kingdom of Naples, grant a concordat with the Confederation of the Rhine (association of German states under French protection) on the same lines as that agreed with France, or join in the alliance against Britain. |
| 28 February 1808 | Austrian Empire, France, Europe [trade] | Austria joins the French emperor Napoleon I's Continental System and supports the closure of European ports to Britain. |
| 19 March 1808 | Spain [administration] | Charles IV of Spain abdicates in favour of his son, Ferdinand, being too closely associated with the francophile policy of his ousted chief minister, Manuel de Godoy. |
| 20 April 1808 | France [births and deaths] | Louis-Napoléon Bonaparte (Napoleon III), emperor of France 1852–71, born in Paris, France (–1873). |
| December 1808 | USA [elections] | Americans elect James Madison of the Democratic-Republican Party as US president and George Clinton as vice-president. |
| 31 December 1808 | France [chemistry] | French chemist Joseph-Louis Gay-Lussac publishes The Combination of Gases, in which he announces that gases combine chemically in simple proportions of volumes. |
