Abraham Lincoln was the 16th President of the United States, serving from 1861 until his assassination in 1865. He is widely regarded as one of the greatest leaders in American history. Lincoln is best known for his commitment to preserving the Union and ending slavery. He issued the Emancipation Proclamation in 1863, freeing all slaves in Confederate territory. He also oversaw the passage of the 13th Amendment to the Constitution, which abolished slavery throughout the United States. Lincoln's leadership during the Civil War and his commitment to freedom and equality have made him a beloved and revered figure in American history.