Example image of eyePlorer eyePlorer map for '1791': Common year starting on Saturday Common year starting on Wednesday Gregorian calendar Julian calendar Roman numerals Constitutional Act of 1791 January 25 Lower Canada Parliament of the United Kingdom Province of Quebec (1763–1791) Upper Canada March 2 Paris Semaphore line March 4 U.S. state Vermont April 21 Washington, D.C. Constitution Constitution of May 3, 1791 Europe General sejm May 3 Polish–Lithuanian Commonwealth Flight to Varennes June 20 Members of the French Royal Families Joseph Haydn July 8 University of Oxford Birmingham England July 14 Priestley Riots Champ de Mars, Paris French Revolution July 17 August 4 Ottoman–Habsburg wars Treaty of Sistova August 6 Berlin Brandenburg Gate August 26 John Fitch (inventor) Steamboat United States August 22 Fermín Lasuén