Peninsular War

In 1808 Napoleon, the Emperor of France, was at the peak of his power. He had defeated Austria and Prussia and signed a peace treaty with Russia, ending hostility with them. He had established the continental system and weakened the arch-enemy of France, Britain.

But only six years later, Napoleon was forced to abdicate as Emperor. It was the Peninsular War that marked the beginning of the end of Napoleon's reign. Though Napoleon was confident he would be able to conquer Portugal and Spain quickly, he ended up embroiled in a long and costly war. Let's explore how this shocking reversal of fortunes came about.

Peninsular War Timeline

Peninsular War Definition

The Peninsular War was called as such because it was fought on the Iberian Peninsula, that was made up of Spain and Portugal.

Map of France in the north-west and Spain and Portugal in the south-east. Note how close France and Spain were, even sharing a border. By Whiplashoo21. Creative Commons License. CC-BY-SA-4. Source: Wikimedia Commons.

Peninsular War Summary

In the beginning, Spain was on good terms with Napoleon and France. But in 1808 Napoleon betrayed Spain by invading the country and putting his brother, Joseph, on the throne. Napoleon's war in the Spanish and Portuguese Peninsular marked the beginning of the end. It would spark his demise in mainland Europe and embroil him in a long and costly war. His defeats in Spain and Portugal proved to the rest of Europe that Napoleon’s armies were no longer invincible.

But what changed to sour Napoleon's alliance with Spain? It was really two factors that turned Spain from an ally into a liability for Napoleon: its political instability and its poor military contributions.

Peninsular War Background Napoleon

Napoleon Bonaparte became the first Emperor of France in 1804. He was an exceptionally successful military commander and was a popular figure in France. From the outset of his reign as Emperor, he was embroiled in multiple international conflicts, stemming from previous wars.

Painting of Napoleon, Emperor of the French, by Jacques-Louis David in 1812. Public Domain. Source: Wikimedia Commons.

If Napoleon was facing war on all sides, why then in 1808 did he decide to invade Spain, a country that was already compliant to French interests? The leading Napoleonic historian David Chandler¹ argues that the Peninsular War was a show of Napoleon's sense of invincibility. In 1808 France was at the height of its power, defeating Austria and Prussia and signing a peace treaty with Russia. He had established the continental system, weakening France's old enemy, Britain. Though the Battle of Trafalgar was certainly a blunder, Napoleon's expansion of the French Empire was well underway.

Portuguese Peninsular War

Napoleon expressed his frustration towards Portugal. Portugal was one of Britain’s oldest allies and refused to join the Continental System. This alliance made it easier for Britain to bypass the Continental System's blockade via Portugal and its colonies such as Brazil.

An invasion became necessary to weaken Britain, France's arch-enemy. As a prerequisite to French invasion, the Treaty of Fontainebleau was signed between France and Spain in 1807. The treaty declared that the ruling monarchy was to be exiled and that Portugal was to be divided into three regions between France and Spain. Later that year, Portugal was invaded by the French and Spain and the capital Lisbon was occupied by French troops. The Portuguese monarchy and nobility fled to Brazil before the invasion.

Portuguese Peninsular War Spain Betrayed

Though Portugal and its capital Lisbon were captured, Napoleon did not stop there. Unannounced to Spain, Napoleon’s French troops crossed the Pyrenees in February 1808 and occupied the north of Spain.

Stunned at this betrayal of an ally, the Spain swiftly began pulling its troops from Portugal. But why did Napoleon break France and Spain's alliance in the first place?

Spain's poor military led to resentment from Napoleon who believed they were not pulling their weight in the alliance. In particular, French and Spanish defeat at the hands of the British in the Battle of Trafalgar in 1805 tested their alliance.

Painting of the naval Battle of Trafalgar by J.M.W. Turner in 1822. Public Domain. Source: Wikimedia Commons.

What's more, Napoleon came to learn of Spain's backhanded dealings with Britain, long considered by France as its enemy. Spain's Prime Minister had proposed to Britain that it would abandon the alliance and invade France if Napoleon was weakened in future battles. This was compounded by the fact that Spain's internal political quarrels and corruption. Rivalry between the king Charles IV and his son Prince Fernando meant Spain's court was divided into two.

Napoleon hoped to remove all these problems through a swift invasion and by putting his brother Joseph on the throne. He hoped that by doing so he would reform Spain's military and bolster France's power against Britain.

Spanish Peninsular War

In 1808 Napoleon sent an army of 100,000 troops to conquer Spain and make his brother Joseph the King. As French troops occupied northern Spain, Charles IV was forced to abdicate in favour of his son who was crowned Fernando VII. Napoleon soon forced Fernando VII to abdicate too.

Napoleon installed his brother, Joseph Bonaparte as the King. Joseph Bonaparte was now Joseph I of Spain.

Spanish Peninsular War Iberian Revolt

But French betrayal and invasion only served to unite the Spanish population against Joseph I. French armies marched towards Madrid only to be met with fierce opposition from the locals. In May 1808 the Iberian Revolt broke out, marking the beginning of the Spanish Peninsular War.

Resistance from locals during the Spanish Peninsular War gave birth to the term guerrilla warfare.

Insurrections and riots in other cities followed suit. The Spanish War of Independence had begun.

Peninsular War Battles

The Spanish revolt against Napoleon proved to be fruitful as they not only managed to hold their own against the famous French Imperial Army for over 5 years but also managed to weaken the French army’s reputation as invincible.

Peninsular War Battles Resistance from Spain and Portugal

The Spaniards fought valiantly. They engaged in many battles and though they were largely won by the French, they still managed to make it as difficult for the invading France to achieve victory. When it came to Portugal, it is important to know that conquering a country does not necessarily mean holding it. The British continued to supply the Portuguese and with them, the Spanish continued resisting the French. The French may have won individual battles, but they continuously failed to turn Spain into their subservient state.

From the very beginning of the war, Britain undermined French ambitions. With the landing of Arthur Wellesley in Portugal in 1808, a series of inconclusive battles were fought between the British and the French until 1812. Though neither side won, Britain was able to prevent France from fully controlling Portugal and taking over its military.

Peninsular War Battles Russia

In 1812 Napoleon invaded Russia. The invasion of Russia devastated Napoleon’s army. Napoleon was forced to withdraw much of the French forces from Spain to bolster his army in Russia. With the united force of British, Portuguese and Spanish troops, the newly allied army defeated the French at the Battle of Vitoria in 1813.

Peninsular War Battles and the End of Napoleon

Following his defeat in Russia, the Coalition believed it was the right time to put down Napoleon once and for all. The Coalition was the alliance between Britain, Austria, Prussia, Russia, and now Spain and Portugal, that formed to defeat Napoleon

So began the War of the Sixth Coalition. The war lasted for just over a year from 1813 to 1814. Napoleon was finally defeated. Later that year he abdicated.

With news of Napoleon's abdication, Arthur Wellesley penetrated south-eastern France with his armies and soon the reign of the Bonaparte in Spain was over. Joseph Bonaparte was forced to abdicate, and in his place, Fernando VII returned to the throne. The Peninsular War was over.