1784 was a leap year starting on Thursday (see link for calendar).

Events

• January 6 - the Turks agree to Russia's annexation of the Crimea in the Treaty of Constantinople
• January 14 - The US Congress ratifies the Treaty of Paris with England to end the American Revolutionary War
• February 27 – Count of St Germain dies of pneumonia in Schleswig-Holstein
• February 28 - John Wesley charters the Methodist Church
• August 10 - Jeanne de la Motte fools Cardinal de Rohan - Queen's Necklace Affair begins

• The Japanese famine continues as 300,000 die of starvation
• Benjamin Franklin tries in vain to persuade the French to alter their clocks in winter to take advantage of the daylight
• Benjamin Franklin invents bifocal spectacles
• Antoine Lavoisier pioneers quantitative chemistry
• Britain receives its first bales of imported American cotton
• Emperor Josef II suspends the Hungarian Constitution because of a Revolution in Transylvania
• Huge locust swarm in South Africa

Births

• January 28 - George Hamilton Gordon, 4th Earl of Aberdeen, Prime Minister of the United Kingdom
• March 13 - Jean Moufot, French philosopher and mathematician
• April 5 - Louis Spohr, German violinist and composer (d. 1859)
• October 13 - King Ferdinand VII of Spain
• October 19 - John McLoughlin, Fur Merchant
• October - Sarah Biffen, painter (d. 1850)
• November 24 - Zachary Taylor, 12th President of the United States.

Deaths

• July 1 - Wilhelm Friedemann Bach, German composer (b. 1710)
• August 21 - Junipero Serra, Spanish priest (b. 1713)
• September 8 - Ann Lee, Shaker leader
• December 13 - Samuel Johnson, English writer
• December 26 - Seth Warner, American revolutionary leader