Virginia became the 10th state to join the Union on June 25, 1788. Virginia's first two senators, Richard Henry Lee and William Grayson, took office on March 4, 1789. Virginia's longest-serving senators include Harry F. Byrd, Sr. (1933-1965) and John Warner (1979-2009). Among those who rose to leadership positions are Henry Tazewell, James Murray Mason, and Carter Glass, all of whom served as the Senate's president pro tempore. As vice president, Thomas Jefferson (1797-1801) and John Tyler (1841) served as the Senate's constitutional president or presiding officer. Tyler went on to serve as president of the United States upon the death of William Henry Harrison.