Overview
The Peninsular War (1807–1814) was a prolonged conflict on the Iberian Peninsula between the First French Empire under Napoleon Bonaparte and the kingdoms and peoples of the Iberian Peninsula, including the Spanish Empire, Spain and Portugal. It became one of the most important and exhausting fronts of the broader Napoleonic Wars, drawing in British forces and local irregulars and shaping military and political developments in Europe.
How the war began
At first France and Spain were nominal allies, and in 1807 allied French and Spanish troops together invaded and occupied Portugal to enforce continental policies against Britain. The situation changed abruptly in 1808 when French forces turned on their former partner and became enemies of Spain. Napoleon installed his brother, Joseph Bonaparte, as king of Spain, an act that provoked widespread popular uprisings and organized resistance.
Characteristics of the fighting
The war combined large set-piece battles and sieges with persistent irregular operations. British expeditionary forces, Portuguese troops reorganized under British direction, and Spanish regulars fought alongside countless local partisans. The Spanish popular resistance gave rise to small-scale, mobile bands that harassed French columns and supply lines—actions that led to the adoption of the term guerilla, from the Spanish word for “little war,” to describe guerrilla warfare on a modern scale.
Key events and figures
British commanders, most notably Arthur Wellesley (later the Duke of Wellington), won a series of notable victories and sieges that shifted momentum against the French. Fighting included entrenched sieges of frontier fortresses and decisive battles fought across varying terrain. In the final phase allied forces pressed into southern France, and the campaign reached northern points such as Toulouse as Napoleon’s position in Europe collapsed in 1814.
Notable battles and operations
- Major set-piece battles and sieges across Spain and Portugal that determined regional control.
- Widespread guerrilla actions that disrupted French logistics and tied down sizeable forces.
- Anglo-Portuguese expeditions and coordinated multinational operations that gradually expelled French forces.
Consequences and legacy
The Peninsular War had political and military consequences far beyond the peninsula. Militarily, it drained French manpower and resources and helped to weaken Napoleon’s hold on Europe. Politically, Spanish resistance produced new centers of government and reform—most notably the Cortes that met in Cádiz and produced a liberal constitution in 1812—while Portugal and Britain reinforced their strategic ties. The conflict also left a lasting place in military history for irregular warfare; the word and concept of guerilla entered many languages as a result.
