The Treaty of San Ildefonso is signed on October 1, 1800 between France and Spain, whereby Spain returned the Louisiana territory to France. This treaty was a critical link in the chain of events which led to the 1803 Louisiana Territory Purchase by the United States.
The treaty was basically a territorial exchange; Louisiana tfor France in support of the then, imperial ambitions of Napoleon Bonaparte in North America and Spain received a newly formed kingdom on the Italian peninsula (later known as the Kingdom of Etruria in Tuscany) for the Duke of Parma, the son-in-law of the Spanish King. This treaty was a critical link in the chain of events which led to the 1803 Louisiana Territory Purchase by the United States.
