Example image of eyePlorer eyePlorer map for '1801': Common year starting on Thursday Common year starting on Tuesday Gregorian calendar Julian calendar Roman numerals 19th century Act of Union (1800) Great Britain Ireland United Kingdom of Great Britain and Ireland Ceres (dwarf planet) Dwarf planet Giuseppe Piazzi Chief Justice of the United States January 21 John Marshall February 4 Prime Minister of the United Kingdom William Pitt the Younger Austria February 16 France Treaty of Lunéville War of the Second Coalition Aaron Burr Electoral College (United States) February 19 President of the United States Thomas Jefferson United States House of Representatives Vice President of the United States February 27 United States Congress Washington, D.C. John Adams March 4 Battle of Abukir (1801) March 21 Ralph Abercromby United Kingdom March 23 Paul I of Russia Russia Tsar Alexander I of Russia Admiral April 2 Battle of Copenhagen (1801) Copenhagen Horatio Nelson, 1st Viscount Nelson