Louisiana was ceded by France to Spain in 1762, and restored to the foiTner power in 1800. Three years after, it was ceded by France to the United States. In none of thesfe cessions, was there any specification of bounda- ries. The territory was a vast undefined region west of the Mississippi ; and with rare exceptions, untenanted by civilized inhabitants. It, of course, adjoined the Spanish dominions in Mexico, but the separating line could not easily be ascertained. As the American settlements in Louisiana extended, the question of boundary necessarily became a matter of discussion, between the governments of Spain and the United States. This question was finally settled in 1819, by a treaty with Spain, in which the con- tracting powers severally ceded to each other all claims to territory beyond their respective sides of a defined line.
In 1820, the State of Missouri, formed out of the Lou- isiana territory, was admitted into the Union as a slave State. To facilitate its admission, and to overcome the formidable opposition of the Northern States, to the incorporation into the confederacy of another slaveholding State, the slaveholders proposed and eflfected the celebrated Missouri compromise, a law declaring- that in future slavery should be prohibited north of 30^ -30" north lati- tude.
It was not long however, before it was (Ji.^cuvereJ thai this Missouri compromise, together with the soutliern boundary of the United States, as defined in the Spanish treaty of 1819, had reduced within comparatively narrow limits, the area from Which slave States might hereafter be formed ; with the exception of Florida, the territory south of the Missouri compromise line, was not probably sufficient for more than two States.