If you're referring to Napoleon's Spanish Iberian peninsula campaign between France and the coalition of Spain, Portugal and England from 1808-1814 there were three critical reasons for its failure and one main critical importance for its failure.
The three critical reasons for its failure:
1) Napoleon greatly underestimated the fierceness and will of the Spanish fighting spirit.
2) Chiefly because of reason 1) above, the vastness of the Spanish frontier and the resources required to occupy & hold territory bled his army dry.
3) Napoleon did not expect the coalition arrayed against him to hold as strongly as it did.
The main importance of its failure was that, due to Napoleon's overly ambitious tenancy to overstretch and string-out his resources, his other armies in other theaters of war were left under strengthened.
It’s a or b but Ik it’s not c !
Herbert Clark Hoover (August 10, 1874 – October 20, 1964) was an American engineer, businessman, and politician who served as the 31st president of the United States from 1929 to 1933. A member of the Republican Party, he held office during the onset of the Great Depression.
Alexander the Great ruled from 331 to 323 BC
