Ending the Atlantic slave trade was a long process that involved changing economic circumstances and rising humanitarian concerns. In the late 18th century, European economies began to shift from agriculture to industry. Plantations remained profitable, but Europeans had promising new areas for investment. Also, the need for the slave trade lessened as American slave societies approached the point where they could reproduce enough offspring to meet labor needs. But the humanitarian motive was strong, too. Anti-slavery sentiments began to appear in Europe in the 18th century with roots in Christian religious principles and in the egalitarian philosophy that emerged during the Age of Enlightenment.
By 1750 abolitionists were devoting money and time toward ending the slave trade and slavery itself. Their efforts were aided by the egalitarian ideals of the American Revolution (1775-1783) and the French Revolution (1789-1799) and by such bloody slave rebellions as the Haitian Slave Revolt on the French island of St. Domingue in 1791. Britain outlawed the slave trade in 1807, as did the United States in 1808. The Netherlands followed in 1814, France in 1815, Spain in 1820. It remained for the British, who controlled the world=s most powerful fleet, to enforce anti-slave trade laws, and that was difficult.
Cuba was the last to outlaw slavery, in 1888. ADVANCE u3 Monroe Doctrine, statement of United States policy on the activities and rights of European powers in the western hemisphere. It was made by President James Monroe in his seventh annual address to the Congress of the United States on December 2, 1823 In his two most notable pronouncements, Monroe asserted that European powers could no longer colonize the American continents and that they should not interfere with the newly independent Spanish American republics. He specifically warned Europeans against attempting to impose monarchy on independent American nations but added that the United States would not interfere in existing European colonies or in Europe itself. It eventually became one of the foundations of U.S. policy in Latin America. Because it was not supported by congressional legislation or affirmed in international law, Monroe’s statement initially remained only a declaration of policy; its increasing use and popularity elevated it to a principle, specifically termed the Monroe Doctrine after the mid-1840s