In 1801, Spain ceded the Louisiana Territory to France and President Thomas Jefferson dispatched Robert Livingston and James Monroe to Paris to negotiate cessions of part of that land to the United States. Napoleon Bonaparte had initially acquired the territory to try and rebuild the French Empire in North America but, as tensions with the United Kingdom increasing, he soon decided to concentrate mainly on imperial possessions and satellites in Europe. Thus, in 1803, he offered the entire Louisiana Territory and French holdings in Florida for $11,250,000. The United States also agreed to assume $3,750,000 in claims by Americans against France. Seizing the opportunity to double the size of the United States, Jefferson approved the purchase without first consulting Congress. He soon dispatched the Lewis and Clark Expedition to explore it and guaranteed westward immigration and expansion for the next century.
Peter J. Kastor, The Nation's Crucible: The Louisiana Purchase and the Creation of America (New Haven, CT: Yale University Press, 2004); Roger G. Kennedy, Mr. Jefferson's Lost Cause: Land, Farmers, Slavery, and the Louisiana Purchase (New York: Oxford University Press, 2003); Alexander DeConde, This Affair of Louisiana (New York: Scribner, 1976).