James Knox Polk was born in Mecklenburg, North Carolina in 1785. His family moved to Tennessee's Duck River Valley in 1806 when he was eleven years old, and his father, Samuel Polk, was instrumental in the creation of Maury County and the town of Columbia. In 1813, Polk began his schooling at Zion Presbyterian Church southwest of Columbia, later attended the University of North Carolina, and graduated with top honors in 1818. After passing the bar in 1820, he practiced law in Columbia and entered politics as elected Clerk of the State Senate and then as a member of the Tennessee House Representatives in 1823. He married Sarah Childress in 1824, was elected to the United States House of Representatives in 1825, spent the next fourteen years there, supported President Andrew Jackson, and in 1835 was elected Speaker of the House, becoming the only Speaker to later become president. Polk successfully ran for Governor of Tennessee in 1839, lost two successive reelection bids after his first term, and returned to his law practice in Columbia. In 1844, he emerged as a dark horse presidential candidate at the Democratic National Convention and defeated Henry Clay. After promising to serve only one term, he completed a rigorous agenda as president, extending the US boundary to the Pacific Ocean through negotiations with Great Britain in the Northwest and a war with Mexico in the Southwest, increasing the country's size by approximately one million square miles, and establishing the Independent Treasury system, the modern postal system, the Smithsonian Institution, and the United States Naval Academy. He left the White House in 1849 and died three months later at age fifty-three during a cholera epidemic in Nashville.