John Tyler

John Tyler, Jr. (March 29, 1790 – January 18, 1862) was the tenth President of the United States (1841–1845) and the first to succeed to the office following the death of a predecessor.

A longtime Democratic-Republican, Tyler was nonetheless elected Vice President on the Whig ticket. Upon the death of President William Henry Harrison on April 4, 1841, only a month after his inauguration, the nation was briefly in a state of confusion regarding the process of succession. Ultimately the situation was settled with Tyler becoming President both in name and in fact. Tyler took the oath of office on April 6, 1841, setting a precedent that would govern future successions and eventually be codified in the Twenty-fifth Amendment. At 51 years old, he was the youngest U.S. president to take office to that point (whereas Harrison had been the oldest man to take office as president).

Arguably the most famous and significant achievement of Tyler's administration was the annexation of the Republic of Texas in 1845. Tyler was the first president born after the adoption of the U.S. Constitution, the only president to have held the office of President pro tempore of the Senate, and the only former president elected to office in the government of the Confederacy during the Civil War (though he died before he assumed said office).

Source: Wikipedia (http://en.wikipedia.org)