1800

1800(MDCCC) was anexceptional common yearstarting on Wednesdayin theGregorian calendarand aleap year starting on Sundayin theJulian calendar.It was the 1800th year of theCommon Era(CE) andAnno Domini(AD) designations, the 800th year of the2nd millennium,the 100th and last year of the18th century,and the first year of the1800s.As of the start of the year, the Gregorian calendar was 11 days ahead of the Julian calendar. The Julian calendar was in localized use until 1923.

On March 1 (O.S. February 18), when the Julian calendar acknowledged a leap day, and the Gregorian calendar didn't, the Julian calendar fell one day further behind, bringing the difference to 12 days until February 28 (O.S. February 16), 1900.

Events

• World populationhits 1 billion.
• March 14– Cardinal Barnaba Chiaramonti is electedpopeasPius VII.
• March 21–Pius VIIis ordained.
• April 24– U.S.Library of Congressfounded.
• May 5–Great Britainpasses theAct of Unionto join Great Britain andIrelandinto theUnited Kingdom of Great Britain and Irelandto take effect on 1 January1801.The act is signed by KingGeorge IIIin August.
• May 15–Napoleon Bonapartecrosses the Alps and invadesItaly.
• June 14–Battle of Marengo,Napoleon defeats theAustriantroops nearMarengo, Italy.
• June 2– FirstsmallpoxvaccinationinNorth America,atTrinity, Newfoundland.
• June 27– PaschaJussuf KaramanliofTripolideclares war onSwedenby having the flagpole on the consulate chopped down.
• September 5– The island ofMalta,that was occupied by the French, is conquered by British troops.
• November 1–U.S. PresidentJohn Adamsbecomes the firstPresident of the United Statesto live in the Executive Mansion (later renamed theWhite House).
• November 17– TheU.S. Congressholds its firstWashington, DCsession.
• December 3–Battle of Hohenlinden,the French army defeats the Austrian troops.
• December 24– An assault onNapoleon Bonapartefails inParis.
• December 24–Pierre CoudrinandHenriette Aymer de la Chevaleriefound theCongregation of the Sacred Hearts of Jesus and MaryinParis.
• Invention of thevoltaic pilebyAlessandro Volta:the first chemicalbattery
• Theinfrared radiationis discovered byWilhelm Herschel.
• TheAlthingofIceland,the world's oldestparliament,is abolished.

Births

for more information, seeCategory:1800 births.

Deaths

for more information, seeCategory:1800 deaths.