Abraham Lincoln (February 12, 1809 – April 15, 1865) was an American politician who was the 16th president of the United States from 1861 until his assassination in 1865, during the American Civil War. Just five days after most of the Confederate forces had surrendered and the war was ending, John Wilkes Boothassassinated Lincoln. Lincoln was the first president of the United States to be assassinated. Lincoln has been remembered as the "Great Emancipator" because he worked to end slavery in the United States. Lincoln is ranked in presidential opinion polls as the greatest president in U.S. history.