The presidency of Abraham Lincoln began when he took office as the 16th President of the United States on March 4, 1861. It ended with his death on April 15, 1865. During his presidency he claimed more prerogatives than any other president had done before him. As a result, the small and relatively limited powers of the president grew enormously during his time in office. When Lincoln won the 1860 presidential election, he did it without the support of any of the Southern states. Since the 1830s, Southern states had talked about secession, but it became a serious issue in 1860. Between the election and Lincoln's Inauguration in March of 1861, seven states had seceded from the Union. They formed the Confederate States of America (CSA). When Confederates attacked Fort Sumter on April 12, 1861 and captured it the next day, this started the American Civil War. While having little previous military experience, Lincoln still managed to stand out as a great war president. In 1863, his Emancipation Proclamation freed the slaves in Southern states. It led directly to the abolition of slavery in the United States. Given later that year, his Gettysburg Address is and remains one of the most important speeches in American history. In 1865, as the Civil war was ending he was shot and killed by John Wilkes Booth, a Confederate sympathizer. His death made Lincoln a martyr to the Union cause. He is widely recognized as the greatest president in U.S. history.