Conflicts & Resolutions · Treaty
Third Treaty of San Ildefonso
The Third Treaty of San Ildefonso was a secret agreement signed on 1 October 1800 by which Spain returned Louisiana to France. In exchange Napoleon promised a kingdom in Italy, Etruria, for the son-in-law of King Charles IV of Spain. Spain kept administering the colony until 1803, when France, after briefly taking possession, sold Louisiana to the United States, despite having promised Spain never to cede it to a third power.
Mentioned in 1 state history
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Cite this entry
- APA
- The Epoch Institute. (2026). Third Treaty of San Ildefonso. In The Epoch Institute Encyclopedia. https://the-epoch-institute.org/encyclopedia/third-treaty-of-san-ildefonso
- MLA
- “Third Treaty of San Ildefonso.” The Epoch Institute Encyclopedia, The Epoch Institute, 2026, https://the-epoch-institute.org/encyclopedia/third-treaty-of-san-ildefonso. Accessed .
- Chicago
- The Epoch Institute. “Third Treaty of San Ildefonso.” The Epoch Institute Encyclopedia. 2026. https://the-epoch-institute.org/encyclopedia/third-treaty-of-san-ildefonso.
- Harvard
- The Epoch Institute (2026) ‘Third Treaty of San Ildefonso’, The Epoch Institute Encyclopedia. Available at: https://the-epoch-institute.org/encyclopedia/third-treaty-of-san-ildefonso (Accessed: ).
Last reviewed October 2026Random entry ↻