Via Jack and Jill politics, the following timeline:

• 1793 Upper Canada, by Act Against Slavery
• 1799 New York State introduces gradual emancipation
• 1802 Danish abolish slave trade in Danish colonies
• 1802 Slavery re-introduced in France[1]
• 1803 Lower Canada abolishes slavery
• 1804 Haiti abolishes slavery[2]
• 1807 Abolition of the Slave Trade Act: slave trading abolished in British Empire. Captains fined £100 per slave transported.
• 1807 British begin patrols of African coast to arrest slaving vessels. British West Africa Squadron (Royal Navy) established to suppress slave trading; by 1865, nearly 150,000 people freed by anti-slavery operations
• 1807 Abolition in Prussia, Germany The Stein-Hardenberg Reforms.
• 1808 U.S. abolishes transatlantic slave trade
• 1811 Slave trading made a felony in the British Empire punishable by transportation for British subjects and Foreigners.
• 1811 Spain abolishes slavery at home and in all colonies except Cuba,[1] Puerto Rico, and Santo Domingo
• 1814 Dutch outlaw slave trade
• 1815 British pay Portuguese £750,000 (several hundred million dollars in current values) to cease their trade[3]
• 1817 Spain paid £400,000 by British to cease trade to Cuba, Puerto Rico, and Santo Domingo[3]
• 1815 Congress of Vienna. 8 Victorious powers declared their opposition to slavery
• 1818 Treaty between Britain and Spain to abolish slave trade [4]
• 1818 Treaty between Britain and Portugal to abolish slave trade [4]
• 1818 France and Holland abolish slave trading
• 1819 Treaty between Britain and Netherlands to abolish slave trade [4]
• 1821 Ecuador, Colombia, Venezuela abolish slavery
• 1821 Liberia founded by USA as state for emancipated slaves.
• 1823 Chile abolishes slavery[2]
• 1827 Treaty between Britain and Sweden to abolish slave trade [4]
• 1829 Mexico abolishes slavery[2]
• 1831 Bolivia abolishes slavery[2]
• 1835 Treaty between Britain and France to abolish slave trade [4]
• 1835 Treaty between Britain and French and Danish to abolish slave trade [4]
• 1836 Portugal abolishes transatlantic slave trade
• 1838 Slavery abolished throughout the British empire, excluding India, Sierra Leone, Nigeria, Gambia, Aden, Burma and Hong Kong.[5]
• 1839 British and Foreign Anti-Slavery Society founded, now called Anti-Slavery International
• 1839 Indian indenture system made illegal
• 1840 Treaty between Britain and Venezuela to abolish slave trade [4]
• 1841 Quintuple Treaty is signed; England, France, Russia, Prussia, and Austria agree to suppress slave trade[2]
• 1842 Webster-Ashburton Treaty between Britain and US
• 1842 Uruguay abolishes slavery[2]
• 1843 Treaty between Britain and Uruguay to suppress slave trade [4]
• 1843 Treaty between Britain and Mexico to suppress slave trade [4]
• 1843 Treaty between Britain and Chile to suppress slave trade [4]
• 1843 Argentina abolishes slavery[1]
• 1843 Treaty between Britain and Bolivia to abolish slave trade [4]
• 1845 36 British Navy ships are assigned to the Anti-Slavery Squadron, making it one of the largest fleets in the world.
• 1847 Sweden abolishes slavery[6]
• 1848 Denmark abolishes slavery[6]
• 1848 Slavery abolished in all French and Danish colonies[2]
• 1848 France founds Gabon for settlement of emancipated slaves.
• 1848 Treaty between Britain and Muscat to suppress slave trade [4]
• 1849 Treaty between Britain and Persian Gulf states to suppress slave trade [4]
• 1850 USA: Fugitive Slave Law of 1850
• 1851 Brazil ends slave trade[2]
• 1854 Peru abolishes slavery[2]
• 1854 Venezuela abolishes slavery[2]
• 1860 Slavery abolished in British occupied India.
• 1861 Russia frees its population in the Emancipation reform of 1861.[1]
• 1862 Treaty between USA and Great Britain for the suppression of the slave trade (African Slave Trade Treaty Act)[4].
• 1862 Cuba abolishes slave trade[2]
• 1863 Slavery abolished in Dutch colonies[2]
• 1863 U.S. frees southern slaves through the Emancipation Proclamation
• 1865 U.S. abolishes slavery (The Thirteenth Amendment)[2]

Via the flow of history and WikiPedia.