Slavery in America began when the first African slaves were brought to the North American colony of Jamestown, Virginia, in 1619, to aid in the production of such lucrative crops as tobacco. Slavery was practiced throughout the American colonies in the 17th and 18th centuries, and African-American slaves helped build the economic foundations of the new nation. The invention of the cotton gin in 1793 solidified the central importance of slavery to the South’s economy. By the mid-19th century, America’s westward expansion, along with a growing abolition movement in the North, would provoke a great debate over slavery that would tear the nation apart in the bloody American Civil War (1861-65). Though the Union victory freed the nation’s 4 million slaves, the legacy of slavery continued to influence American history, from the tumultuous years of Reconstruction (1865-77) to the civil rights movement that emerged in the 1960s, a century after emancipation.