The American Civil War, widely known in the United States as simply the Civil War as well as other sectional names, was fought from 1861 to 1865. Seven Southern slave states individually declared their secession from the United States and formed the Confederate States of America, known as the "Confederacy" or the "South". They grew to include eleven states, and although they claimed thirteen states and additional western territories, the Confederacy was never recognized by a foreign country. The states that did not declare secession were known as the "Union" or the "North". The war had its origin in the fractious issue of slavery, especially the extension of slavery into the western territories. After four years of bloody combat that left over 600,000 Union and Confederate soldiers dead, and destroyed much of the South's infrastructure, the Confederacy collapsed, slavery was abolished, and the difficult Reconstruction process of restoring national unity and guaranteeing civil rights to the freed slaves began.