Sla′very, the condition of a man who belongs to a master, who has the right to employ him and treat him as he pleases. It probably arose first from captives made by war. It was general among ancient nations, including the Jews. In Greece slaves were employed not only for domestic service, but as bakers, tailors, seamen, miners, soldiers and police. They usually were mildly treated and were often freed. A slave was not allowed to wear his hair long or to enter the gymnasia and public assemblies, but could appear in the temples and at festivals. At one time there were 200,000 slaves in Attica, three times the number of the freemen. Roman slavery was very severe, as is seen by their gladiatorial combats. Old and useless slaves were often left to starve on an island in the Tiber. The cruelty of the masters was gradually softened by the law, a very cruel one being obliged to sell his slaves. The slave could not own property, though sometimes allowed a small portion of his gains when in trade, and could not testify in the courts. In Britain the Anglo-Saxons made slaves of the Celts and other natives, and had a regular trade with the continent in Irish slaves; but with the Norman conquest slavery was merged into serfdom. The traffic in slaves continued among Mohammedan nations, Christian captives being sold as slaves in the markets of Asia and Africa. The Barbary corsairs, down to 1812, carried off large numbers from the coasts of Europe into slavery. Cervantes, for five years a slave, reports 25,000 Christian slaves in Algiers alone. During the middle ages in Europe the class called serfs were, practically, slaves. They were usually attached to the soil and could be transferred with the land they tilled. They could not hold property, but their oath was taken in evidence and, if injured, they were protected by law.

Serfdom died out in England and in Scotland gradually, a curious form remaining in Scotland to the end of the 18th century. Colliers and salt workers were bound by law, on entering a coal-work or salt-mine, to life-service there; their labor was transferred with the ground; and their sons could follow no other trade nor seek employment in other mines. In France the Revolution swept away the last remains of serfdom, and in Italy, it had ended in the 15th century. It was abolished in 1781 in Bohemia and Moravia, and entirely destroyed in Prussia by the reforms of the 19th century, though the mass of the peasants had been free since the end of the 13th century, while Russia put an end to the system in 1861.

Negro slavery of modern times was a result of the discovery of America, the Spanish introducing them first into the New World to work their mines and plantations. They were first used to any extent in Haiti, in San Domingo. Sir John Hawkins was the first English slave-trader, followed by others, until England had carried to America 300,000 slaves between 1680 and 1700, and 610,000 into Jamaica alone between 1700 and 1786. The slave-trade was very inhuman, the negroes being so crowded on the ships that a large proportion died on the passage. The first efforts to restrain slavery were made to stop the slave-trade. In 1787 a society for this purpose was formed in London, with such supporters as Clarkson, Wilberforce, Zachary Macaulay and Sharp. After years of struggle the abolition bill, making all slave-trading by British subjects illegal after Jan. 1, 1808, became a law on March 7, 1807. The movement continued until, on Aug. 28, 1833, an emancipation bill was passed giving freedom to all slaves in the British colonies. Slavery was abolished in the French colonies in 1848, in the Dutch ones in 1863 and in Brazil in 1888.

When the American colonies became the United States in 1776, there were 300,000 slaves in the country, and in 1790, at the taking of the first census, they numbered 697,897, and were in all the states except Vermont and Massachusetts, to which Maine then belonged. The northern states gradually abolished slavery, Pennsylvania having 64 as late as 1840. In the south many, with such leaders as Washington and Jefferson, opposed slavery until the invention of the cotton-gin made it profitable and developed it, when even the renewing of the slave-trade with Africa, abolished by the United States in 1808, was advocated. The contest between the upholders and the opposers of the system, beginning in the north with the formation of societies for the gradual abolition of slavery and carried on by literature, lectures and, finally, political parties, was met in the south by demands for enlarged territory and national laws protecting their slave-property in the free states. The Pennsylvania Abolition Society was founded in 1775, with Benjamin Franklin as president, and the New York Society, with John Jay and Alexander Hamilton as leaders. In 1831 Garrison established The Liberator, the antislavery journal. The formation of a northern republic, free from slavery, was the hope of the extreme abolitionists, as the formation of a southern republic founded on slavery was the aim of the extreme proslavery party. The contest ended in the Civil War of 1861-65, in the course of which the proclamation of emancipation was issued by Lincoln, Jan. 1, 1863, setting free nearly 4,000,000 slaves, and confirmed in 1865 by an amendment to the constitution approved by 27 of the 36 states.

Slavery still exists, and the slave-trade is carried on by Arab slave-traders in the interior of Africa, the tracks of their caravans being whitened by the bones of those who have died on the journey, and by the Portuguese. The Congo Free State, the foundation of missions and the encouragement of trade by the British and German companies, with the help of all Christian governments, will, it is hoped, finally end the terrible traffic, in which over 90,000,000 Africans have been enslaved. Consult Clarkson's History of the Slave-Trade and Wilson's Rise and Fall of the Slave-Power in America.