The President, Directors and Company, of the Bank of the United States, commonly known as the First Bank of the United States, was a national bank, chartered for a term of twenty years, by the United States Congress on February 25, 1791. It followed the Bank of North America, the nation's first de facto central bank. Establishment of the Bank of the United States was part of a three-part expansion of federal fiscal and monetary power, along with a federal mint and excise taxes, championed by Alexander Hamilton, first Secretary of the Treasury. Hamilton believed a national bank was necessary to stabilize and improve the nation's credit, and to improve handling of the financial business of the United States government under the newly enacted Constitution.
Source: Wikipedia