Slavery has existed since the origins of written history and probably long before. It is discussed in the Hebrew Bible which set standards for enslaving persons and treatment of slaves. Excepting a few schools of philosophy, nearly all Greeks thought slavery was the natural condition of many human beings. Most important among those Greeks advocating slavery were two of humankind''s greatest minds, Plato and Aristotle. Enslavement of one with a slave soul was considered just and freeing such a person was considered unjust. The Romans ignored the Greek philosophizing about slavery, but practiced it on a massive scale, frequently enslaving captives from various wars. Rome''s greatest philosopher Cicero defended slavery. Rome was plagued by several servile revolts, the best known of which was led by Spartacus. Slavery was practiced throughout Europe and the Middle East following the fall of Rome. There was no racial dimension or consideration until Spain and Portugal began to enslave native aborigine in the newly discovered Western Hemisphere. To save these natives from involuntary servitude, the Church promoted importation of Africans. Following decades of profitable slave trade, England led the way in abolishing slavery. Other nations followed, including the United States, although that emancipation required a major internal war. Southern slave holders consistently defended the enslavement of presumed racial inferiors and claimed that slavery was beneficial to them. Southern slave holders produced volumes of literature supporting slavery, some of which referred to the Greek philosophers.