Southerners got butthurt that Lincoln, a known abolitionist (person who was against slavery) got elected president since slave labor was important to their economies. So most of the Southern states broke off from the U.S. and formed their own country, the Confederate States of America, and war broke out. Eventually Lincoln issued the Emancipation Proclamation which basically said the slaves living in the South were to be free. Important Union generals included Ulysses S. Grant and William T. Sherman (this guy basically tore the South a new butthole), and Confederate generals included Stonewall Jackson and Robert E. Lee.
