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Events on Wednesday 1 October 1800 1
1800Treaty of San IldefonsoSpain secretly cedes Louisiana back to FranceIn a secret treaty signed at San Ildefonso, Spain agreed to transfer the Louisiana territory in North America back to France in exchange for territorial concessions in Italy. The transfer remained secret for two years. It set the stage for the Louisiana Purchase, when Napoleon sold the territory to the United States in 1803.