The presidency of John Tyler began on April 4, 1841, when John Tyler became President of the United States upon the death of President William Henry Harrison, and ended on March 4, 1845. He had been Vice President of the United States for only 31 days when he assumed the presidency. The tenth United States president, he was the first to succeed to the office intra-term without being elected to it. To forestall constitutional uncertainty, Tyler took the presidential oath of office on April 6, moved into the White House, and assumed full presidential powers, a precedent that would govern future extraordinary successions and eventually become codified in the Twenty-fifth Amendment.