Iberian Peninsula. Siege of Barcelona in 801. Louis the Pious (778-840) began the conquest of the Muslim-held city of Barcelona. On 3 April 801, after a hard siege of the city, the inhabitants themselves opened the gates of the city to the Frankish army of Louis the Pious, led by William of Gellone, Duke of Toulouse (755-812). Barcelona became the capital of the County of Barcelona. Frankish soldiers protected behind a mantlet. Engraving by Serra Pausas. "Glorias Espanolas" (Glories of Spain). Volume II. Published in Barcelona, 1890.