Answer:
Guerrilla warfare in the Peninsular War refers to the armed actions carried out by non-regular troops against Napoleon's Grand Armée in Spain and Portugal during the Peninsular War. These armed men were a constant source of harassment to the French army, as described by a Prussian officer fighting for the French: "Wherever we arrived, they disappeared, whenever we left, they arrived — they were everywhere and nowhere, they had no tangible center which could be attacked. The Peninsular War was significant in that it was the first to see a large-scale use of guerrilla warfare in European history and as a result of the guerrillas, Napoleon's troops were tied down on the Iberian peninsula, unable to conduct military operations elsewhere on the continent.The strain the guerrillas caused on the French troops led Napoleon to dub the conflict the "Spanish Ulcer."
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