Iceland abolished slavery in A.D. 1117.
Pope Paul III forbid the enslavement of indigenous peoples in the America's in 1537. Forced displacement and systematic oppression was still okay. Oh ... and of course Africans could still be enslaved.
Portugal banned the buying and selling of Chinese slaves in 1595. Black slaves still super cool with them.
Russia abolished slavery in 1723.
Sierra Leone was founded by the British as a colony for freed slaves in 1787. Domestic slavery, perpetuated by the wealthy, wasn't outlawed there until 1928.
Haiti declared independence from France in 1804, perhaps the only truly successful slave revolt in modern history.
The Abolition of the Slave Trade Act was passed in Britain in 1807. The United States banned the trade the following year though President Thomas Jefferson called Congress to make the slave trade illegal in 1806. A slew of nations abolished slavery or slave trading in the decades that followed.
The last slaves were freed in Mexico in 1829, but when the Republic of Texas was established in 1836, it legalized slavery there.
President Lincoln issued the Emancipation Proclamation in 1863, one of the most important executive orders in United States history. It was followed by passage of the 13th amendment two years later.
Oklahoma, then Indian Territory, didn't abolish slavery until 1866.
In the 80 years following the British abolition of the slave trade, Brazil imported an additional 1 million African slaves and became the world's leading producer of coffee. Slavery was finally abolished in Brazil in 1888.
The British, who had abolished the slave trade in 1807, continued using Indians as indentured servants on a large scale until 1917. Many long-established Indian populations around the world began during this period of forced displacement.
Slavery continued legally in Ethiopia until 1942 when it was officially abolished by Emperor Haile Selassie.
Slavery was still legal in the nations of Saudi Arabia, Yemen, UAE, and Oman until the 1960s.
The most recent nations to make slavery a crime were Niger (2003) and Mauritania (2007).
Slavery is now officially illegal in all nations. However, estimates suggest that more than 35 million people remain enslaved around the world.
The Global Slavery Index - http://www.globalslaveryindex.org/findings/
The UN International Labor Organizatin - http://www.ilo.org