1820
year
1820 (MDCCCXX) was a leap year starting on Saturday of the Gregorian calendar and a leap year starting on Thursday of the Julian calendar, the 1820th year of the Common Era (CE) and Anno Domini (AD) designations, the 820th year of the 2nd millennium, the 20th year of the 19th century, and the 1st year of the 1820s decade. As of the start of 1820, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.
Events
January–March
January 1 – A constitutionalist military insurrection at Cádiz leads to the summoning of the Spanish Parliament to meet on March 7, becoming the nominal beginning of the "Trienio Liberal" in Spain.
January 8 – The General Maritime Treaty of 1820 is signed between the sheikhs of Abu Dhabi, Sharjah, Ajman, Umm al-Quwain and Ras Al Khaimah (later constituents of the Trucial States) in the Arabian Peninsula and the United Kingdom.
January 27 (NS, January 15 OS) – An Imperial Russian Navy expedition, led by Fabian Gottlieb von Bellingshausen in Vostok with Mikhail Petrovich Lazarev, sights the Antarctic ice sheet.
January 29 – King George IV becomes the new British monarch upon the death his father George III after 59+ years on the throne. The elder George's death ends the 9-year period known as the British Regency.
January 30 – British Royal Navy captain Edward Bransfield, an Irishman, becomes the first person to positively identify Antarctica as a land mass.
February 6
Capture of Valdivia: Lord Cochrane occupies Valdivia in the name of the Republic of Chile.
A group of 86 free African American colonists sail from New York City to Freetown, Sierra Leone, with a goal of creating a home for freed American slaves, to be called "Liberia".
The public source identifies “1820” as year. This brief keeps that definition visible, then builds a research path around year.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Aug 11, 2026. The linked authority identifier is Q6973. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1820 and 1923.
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This entry incorporates text from “1820” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.