Before the European settlers arrived in America even the Native Americans had their own slaves. Slavery was a very argumentative issue in America and, in fact, was the root cause of both the Haitian revolution and the American Civil War. The importation of slaves to Europe began when the Portuguese Crown gave up its monopoly of the slave trade in Europe leading to private ownership of slaves. This caused the European settlers, especially the Portuguese, to bring more slaves to the Americas directly from Africa. The Spanish were the first to use African slaves in the New World on islands such as Cuba and Hispaniola with the first African slaves arriving in Hispaniola in 1501. By 1750, slavery was established as a legal institution in all of the 13 colonies and contributed to almost five percent of the England 's revenues. The enslavement of humans and the denial of basic human rights to slaves has been the basis of several wars such as the Haitian revolution, the American Civil War and numerous slave rebellions in America. The main reason behind the American Civil War was, indeed, slavery. The Republican Party in America was determined to end slavery, whereas many leaders in the Southern states wanted slavery to continue or they threatened to secede from the Union. In 1860, after Abraham Lincoln won the presidency, the southern states did secede from the Union, which, along with the issue of slavery, triggered the Civil War. After the victory of the Union forces in the