James Knox Polk ( November 2, 1795 - June 15, 1849) was the eleventh President of the United States. Historians termed him as the least known consequential President of the United State. James Knox Polk was in office from March 4, 1845 to March 4, 1849. He promised to serve a single term in office and did not run for re-election. After 3 months as an ex-president, he died of cholera. Scholars rank him favourably on the list of greatest presidents for his ability to set an agenda and achieve all of it.