The Peninsula War
...the French navy from enforcing the Continental System. Knowing that Britain opposed him, and recognizing Britain’s naval strength, Napoleon feared an attack on France by sea from the coast of the Iberian Peninsula. He felt particularly vulnerable from that direction because Portugal, an old ally of Britain, had openly refused to join the Continental System, and because Spain, too, opposed Napoleon. It was clear to him that he must prevent an attack from the Iberian coast, and to do so he must have military control over Portugal and Spain. The aim of Mastery over Europe, enforcement of the Continental System, European resentment, and Britain’s opposition to Napoleon, were, therefore, the main causes of the Peninsula War. A subsidiary or less important cause was, perhaps, Napoleon’s desire to give his brother Joseph the chance to rule Spain. This seemed a possibility since the Spanish King Charles IV was not popular with his people In November 1807, Napoleon sent an army, under Marshal Junot, for the purpose of invading and taking control of Portugal. The move was successful, at first. Lisbon was captured on December 1, and the Portuguese family, and the entire administration fled to Brazil, then a Portuguese colony. The French army then turned against Spain. There, the Spanish people had replaced Charles IV with his son Ferdinand, but following the defeat of combined Spanish and British forces, Napoleon removed the Spanish royal family, and made his brother Joseph King of Spain. But this was the beginning of Napoleon’s failure in the Peninsula War. The main causes of Napoleon’s failure in the Peninsula War were that he under-estimated (1) the strength of the Spanish and Portuguese national resentment, and (2) Britain’s willingness to commit its armed forces to the effort to drive Napoleon from the Peninsula. Portuguese and Spanish resentment gave rise to a new kind of irregular warfare carried out by autonomous units without a central command. This warfare came to be known by its Spanish name “guerilla” warfare. By this means Spanish and Portuguese resistance groups could attack and engage the regular French troops at a number of different locations, using surprise and speed to cause maximum disruption. The “guerilla” fighters were armed and equipped by Britain. By doing so, Britain carried out its purpose through Spanish and Portuguese soldiers, and did not have to send its own soldiers into battle. To suppress these guerilla attacks and turn the tide of the war, Napoleon himself arrived in 1808, with 200,000 soldiers, and for a time the French forces were victorious. But in 1809, the British sent Sir Arthur Wellesley (later the Duke of Wellington) to join and lead the Spanish aga...