The presidency of Abraham Lincoln began on March 4, 1861, when he was inaugurated as the 16th President of the United States, and ended upon his assassination and death on April 15, 1865, 42 days into his second term. His election served as the immediate impetus for the outbreak of the American Civil War. After being sworn in as president, Lincoln refused to accept any resolution that would result in Southern secession from the Union. The Civil War began weeks into Lincoln's presidency with the Confederate attack on Fort Sumter, a federal installation located within the boundaries of the Confederacy. Political historians have long held Lincoln in high regard for his accomplishments and personal characteristics. Alongside George Washington and Franklin D. Roosevelt, he has been consistently ranked both by scholars and the public as one of the top three greatest presidents, often as number one.