Example image of eyePlorer eyePlorer map for '1804': Gregorian calendar Julian calendar Leap year starting on Friday Leap year starting on Sunday Roman numerals France January 1 Republic Revolution Slavery February 14 First Serbian Uprising Serbian revolution Ottoman Empire Principality of Serbia February 15 New Jersey Northern United States February 16 First Barbary War Stephen Decatur USS Philadelphia (1799) February 18 Ohio University Abercynon Cornwall February 21 Merthyr Tydfil Penydarren Richard Trevithick South Wales Steam locomotive John Wedgwood (1766–1844) March 7 Royal Horticultural Society Louisiana Purchase Louisiana Territory March 10 St. Louis, Missouri United States Civil law (legal system) March 21 Napoleonic code April 2 Armed merchantman HMS Apollo (1799) Portugal April 5 High Possil meteorite Possilpark