The American Civil War, fought from 1861 to 1865 between the United States of America, or Union, and the Confederate States of America, or Confederacy, was a military conflict over states rights and the extension of slavery into the western territories. Union and Confederate forces together served 3,263,000, with 529,330 killed and 418,206 wounded. Sometimes called the War Between the States or the War of the Rebellion, the conflict was watched by the world as a test of whether a nation conceived in liberty would long endure. President Lincoln’s Emancipation Proclamation brought freedom to 4 million black slaves.