The Louisiana Purchase was one the largest land mass ever purchased by the United States at one time. This was Thomas Jefferson's most glorious achievement during his term. He achieved much throughout his term but nothing compared to the acquisition of the huge province called Louisiana. .
The French originally settled the Province of Louisiana in the early 18th century. In the year 1762 it was given to Spain because of a secret treaty that was established between the two countries. A year later the vast region east of the Mississippi, with the exception of New Orleans was lost by Spain in the Seven Years War to Great Britain.
By 1800, another secret treaty came about this time created by Napoleon I. This forced Spain to return what was left of Louisiana to France. In 1802, two acts that President Thomas Jefferson regarded as "hostile to the interests of the U.S." Napoleon had sent forces to New Orleans and to Santo Domingo (now the Dominican Republic) to put down a rebellion that had arose there. During this period French forces around the Mississippi revoked all privileges that the United States merchants had to deposit foreign goods duty-free at the port at New Orleans. .
Thomas Jefferson, in retaliation to the events prior, sent John Monroe to Paris to assist the American minister to France, Robert R. Livingston. He was sent to Paris to effect on of four proposed plans for the United States. The first plan was the purchase of eastern and western Florida and all of New Orleans. The second plan was the purchase of New Orleans alone. The third plan was to purchase all of the land on the eastern bank of the Mississippi River, so that the United States could build a port. The last plan was to obtain all rights of navigation and deposit at the New Orleans port that they once had. .
During normal circumstances the French would not have agreed to any of these proposals, but because their entire army in Santo Domingo was wiped out by yellow fever and war with Great Britain was inevitable Napoleon decided on something else.