The Brutal And Merciless Peninsular War – Napoleon’s Invasion of Spain Was The Downfall Of The Emperor

By Augusto Ferrer-Dalmau - CC BY-SA 3.0
By Augusto Ferrer-Dalmau - CC BY-SA 3.0

Invading an Ally

Before France invaded Spain in October 1807, the two countries were allies. However, Spain was not the reliable ally Napoleon wished for. Factions in the Spanish court were pushing the King towards abandoning the French alliance and launching an invasion across the Pyrenees.

More importantly, the Iberian Peninsula stood in the way of Napoleon’s plans to defeat his greatest rival, Britain. His plan was to destroy the British economy through the Continental System, a blockade on British trade.

For this idea to work, however, it relied on Europe not trading with Britain. Spain was not a staunch supporter of the system, and Portugal, on the far side of Spain from France, was one of Britain’s biggest markets in Europe.

Napoleon cast aside their alliance and led his troops into Spain.

Three Invasions of Portugal

Having crossed through Spain, the French invaded Portugal. It was the first of three invasions in only four years, as the French struggled to bring the Portuguese under control.

Changing Kings

Once in control of Spain, Napoleon bullied both King Charles IV and his son Ferdinand into giving up their throne. He then brought in his brother, Joseph, as King of Spain. Joseph had some experience as a ruler, as Napoleon had previously put him in charge of Naples. This nepotistic approach allowed Napoleon to ensure he could rely on the monarchs of satellite states; family members who owed their positions to him.

Loss of the Colonies

The French invasion and the monarchy’s time in exile led to Spain’s loss of its colonies.

A rebel government was founded in Spain to fight against French control. The Latin American colonies felt they should be represented in the government as they had not been before. Conservatives and those with old world interest resisted. As a result, more people in the colonies came to resent Spanish rule. A series of revolts broke out, leading to the eventual liberation of the colonies years later.

The Source of the Word “Guerrilla”

The term “guerrilla warfare” came into the English language due to the French invasion of Spain.

Resistance to military rule by armed civilians was by no means unprecedented. Nor was the sort of irregular fighting it led to, as soldiers and civilians alike attacked using ambushes, sabotage, and hit and run raids. Up to then, there had been no word for that sort of fighting. The Spanish provided one – “guerrilla,” meaning “little war.” As the British became involved in the fighting in Spain and Portugal, they picked up the word from locals and it entered the English language.

Terror Tactics

The desperate, irregular nature of the guerrilla war led to the use of terror tactics often adopted by and against freedom fighters and terrorists. French soldiers were mutilated, decapitated, and allegedly buried alive. The French fought back by hanging partisans from trees, leaving their bodies out as a warning.

Regular soldiers on both sides of the war came to see the guerrillas as savage and uncivilized. British troops, as well as French, looked at the Spanish with a wary eye.

The War That Made Wellington

The Peninsula Campaign was the war that made the career of Sir Arthur Wellesley, who by its end had been made the Duke of Wellington.

Wellesley had previously distinguished himself as an officer in India and Denmark. When the British arrived in Portugal, with the intention of pushing on from there to liberate Spain, he was not in charge. A government inquiry into the conduct of the war led to the removal of his superiors. Only Wellesley came out of the investigation looking good, so he was given command of the British forces in the Iberian Peninsula in April 1809.

From then on he showed the skill with which the British would push the French back and defeat Napoleon at Waterloo. Using skirmishers and placing his troops on the reverse slopes of high ground, he was able to counter French tactics. His attention to diplomacy and logistics, as well as strategy and tactics, brought the British and their Peninsula allies a string of victories.

His success was reflected in his ever increasing rank as he was made a Viscount in 1809, Earl in 1812, Marquess later that year, and Duke in 1814. Militarily, he was made into a British Field Marshal in 1813, as well as being appointed marshal-general by the Portuguese and generalissimo by the Spanish.

Saved by Wars Elsewhere

At first, the French stormed through Spain and into Portugal. It looked as if they would win the campaign.

Then the situation was transformed by events elsewhere in Europe. A revolt by the Tyroleans in 1809 created an excuse for Austria to start fighting the French again. As a new coalition formed against him, Napoleon was forced to leave Spain and deal with the political and military consequences. Without his inspiring leadership, the French were much weaker.

The Maid of Saragossa

One of the famous heroes of the war was Agostina Zaragoza, “the Maid of Saragossa.” She rose to prominence during the defense of Saragossa against the French. Her lover was killed while crewing a canon and she took his place, keeping the gun in action. She became the subject of books, poems, and paintings, a symbol of resistance.

Marshal Soult

Marshal Jean-de-Dieu Soult commanded the French forces throughout much of the war in Spain. He fought the British as they pursued the French across the Pyrenees and into France. He earned the respect of many of his opponents, although Wellington felt he was overrated and prone to hesitation on the battlefield.


Mike Duncan, Revolutions Podcast.

Alan Forrest (2011), Napoleon.

Philip Haythornthwaite (2004), The Peninsular War: The Complete Companion to the Iberian Campaigns 1807-14.

Andrew Knighton

Andrew Knighton is one of the authors writing for WAR HISTORY ONLINE