Both the Spanish King and the Spanish people were dazzled and awed by the splendor of Napoleon's victories.

Napoleon's magnificent and wayward genius was always striving after more than merely European empire.

As throne after throne went down before him he planned conquests which should include the interminable wastes of snowy Russia, and the sea-girt fields of England; and he always dreamed of yet vaster, more shadowy triumphs, won in the realms lying eastward of the Mediterranean, or among the islands and along the coasts of the Spanish Main.

In 1800 his dream of Eastern conquest was over, but his lofty ambition was planning for France the re-establishment in America of that colonial empire which a generation before had been wrested from her by England.
The Treaty of San Ildefonso.
The need of the Spaniards seemed to Napoleon his opportunity.

By the bribe of a petty Italian principality he persuaded the Bourbon King of Spain to cede Louisiana to the French, at the treaty of San Ildefonso, concluded in October, 1800.