The outcome of the U.S. Civil War was the definitive end of slavery in the United States. The war, which lasted from 1861 to 1865, primarily aimed to preserve the Union but also addressed the contentious issue of slavery. The Emancipation Proclamation issued by President Abraham Lincoln in 1863 declared the freedom of all enslaved people in Confederate-held territories. Following the Union's victory, the 13th Amendment to the Constitution was ratified in December 1865, abolishing slavery throughout the entire nation. This monumental change not only freed millions of African Americans but also marked a significant shift in social, political, and economic dynamics in the U.S.