In June 1808, Napoleon Bonaparte installed his brother Joseph on the Spanish throne as a way of securing French control of the Iberian Peninsula. It turned out to have the opposite effect. The Spanish people disliked their feckless Bourbon monarchs, but they absolutely hated the meddlesome French. Within weeks, violent revolts sprang up across the country, and the overextended French forces found themselves isolated in hostile territory. In August, having resided in Madrid for only ten days, Joseph was forced to flee to the French border. To make matters worse, during this time a British expeditionary force under the command of Sir Arthur Wellesley landed in Portugal, beginning the six-year Peninsular War.
When Napoleon learned of what had transpired in Spain, he was irate and berated his generals for their incompetence. “I realise I must go there myself to get the machine working again,” he announced, and on 4 November 1808 he crossed the Pyrenees with an army of 130,000 men, mostly veterans of previous campaigns. His arrival in Spain immediately tipped the scales bade in favour of the French. On 10 November he won a crushing victory at the Battle of Gamonel, and two weeks later the French defeated another Spanish army at Tudela. What was left of the shattered Spanish forces retreated south towards Madrid with Napoleon himself in vigorous pursuit at the head of a 45,000-strong vanguard.
MOUNTAIN PASSES
Napoleon now faced another obstacle - one that he could not simply outmanoeuvre on theThe Sierra de Guadarrama mountains run roughly 80 kilometres (50 miles) across central Spain, shielding Madrid from an attack from the north. In 1808, there were two main passes the French could have taken: one near the town of Guadarrama northwest of Madrid, and another that ran through the sleepy mountain village of Somosierra almost directly north of the capital. Napoleon chose the latter, because it was the quickest route and located along the main road south from Burgos, where he was regrouping his army.
