James Monroe was the fifth President of the United States, serving from 1817 to 1825. He is best known for the Monroe Doctrine, a key policy that warned European nations against interfering in the Americas. Monroe's presidency is often associated with the "Era of Good Feelings," a time marked by national unity and political harmony following the War of 1812. Before becoming president, Monroe was a soldier in the American Revolutionary War and held various government positions, including Secretary of State and Secretary of War. He played a significant role in the expansion of the United States, including the acquisition of Florida from Spain in 1819.