WHAT HAPPENED IN 1821.
Look what happened the 1821.

Alexander Island is first discovered by Fabian Gottlieb von Bellingshausen. (28. January 1821)

Greek War of Independence: Alexander Ypsilantis crosses the Prut river at Sculeni into the Danubian Principalities. (22. February 1821)

Alexander Ypsilantis starts the Greek War of Independence in Iași, Wallachia (now part of Romania). (23. February 1821)

Greek War of Independence: Alexander Ypsilantis issues a proclamation at Iași, announcing that he had "the support of a great power" (i.e. Russia). (25. February 1821)

Greek War of Independence: First revolutionary act in the monastery of Agia Lavra, Kalavryta. (21. March 1821)

Greek War of Independence: Battle and fall of city of Kalamata. (23. March 1821)

(Julian Calendar) Traditional date of the start of the Greek War of Independence. The war had actually begun on 23 February 1821. The date was chosen in the early years of the Greek state so that it falls on the day of the Annunciation of the Blessed Virgin Mary, strengthening the ties between the Greek Orthodox Church and the newly found state. (25. March 1821)

Patriarch Gregory V of Constantinople is hanged by the Ottoman government from the main gate of the Patriarchate and his body is thrown into the Bosphorus. (10. April 1821)

Emperor Napoleon I dies in exile on the island of Saint Helena in the South Atlantic Ocean. (5. May 1821)

Greek War of Independence: The Greeks defeat the Turks at the Battle of Gravia Inn. (8. May 1821)

The first major battle of the Greek War of Independence against the Turks is fought in Valtetsi. (12. May 1821)

Establishment of the Peloponnesian Senate by the Greek rebels. (26. May 1821)

Badi VII, king of Sennar, surrenders his throne and realm to Isma'il Pasha, general of the Ottoman Empire, ending the existence of that Sudanese kingdom. (14. June 1821)

Decisive defeat of the Philikí Etaireía by the Ottomans at Drăgăşani (in Wallachia). (19. June 1821)

The Battle of Carabobo takes place. It is the decisive battle in the war of independence of Venezuela from Spain. (24. June 1821)

470 prominent Cypriots including Archbishop Kyprianos are executed in response to Cypriot aid to the Greek War of Independence (9. July 1821)

The United States takes possession of its newly bought territory of Florida from Spain. (10. July 1821)

While the Mora Rebellion continues, Greeks capture Monemvasia Castle. Turkish troops and citizens are transferred to Minor Asia coasts. (23. July 1821)

José de San Martín declares the independence of Peru from Spain. (28. July 1821)

Atkinson & Alexander publish The Saturday Evening Post for the first time as a weekly newspaper. (4. August 1821)