The siege of Barcelona of August-17 December 1808 was one of the great missed opportunities of the Peninsular War. The French had seized Barcelona on 29 February 1808, but had failed to secure the lines of communication back to Spain, most notably by not occupying the city of Gerona. This had not mattered in the early days of the French occupation, but in the spring of 1808 large parts of Spain had risen up against the French. The French commander at Barcelona, General Duhesme, found himself dangerously isolated from the main French armies around Madrid, while Spanish-occupied Gerona blocked the main road back to France. In an attempt to restore the situation, Duhesme made two attempts to capture Gerona. His first attempt to besiege Gerona, on 20-21 June 1808, ended after two unsuccessful assaults on the city. The second siege, which lasted from 24 July-16 August, was a much more serious affair. The besieging force was made up of most of the garrison of Barcelona, reinforced by a second French army under General Reille, which had advanced west from Perpignan. Gerona would soon be besieged by a French army 13,000 strong.
Duhesme had made a very risky move. Barcelona was now defended by 3,500 Swiss and Italian troops under the command of General Lecchi. While his position was only threatened by the local somatenes (the Catalan militia, named after the bells used to summon them), this would not matter, for Barcelona was protected by the citadel of Monjuich, but on 23 July, on the day before Duhesme reached Gerona for the second time, the Marquis of Del Palacio landed at Tarragona at the head of a division of regular troops from the garrison of the Balearic Islands. Del Palacio was appointed Captain-General of Catalonia. His first move was to put in place a blockade of Barcelona, first by attacking the French outposts outside the city. On 31 July the last of these outposts, the castle of Mongat, surrendered to Lord Cochrane, who was assisting the Catalans. Lecchi now began to send panicky messages to Duhesme requesting urgent help and claiming that he was surrounded by 30,000 Catalans, who were attacking his outposts.
The second siege of Gerona came to an unsuccessful end on 16 August. Duhesme was harassed all the way back to Barcelona, finally regaining the safety of the city of 20 August, but only after abandoning most of his supplies. 20 August is one of several dates often given as a start date for the siege of Barcelona, but at this point the Spanish were conducting a blockade rather than a regular siege. Del Palacio placed the Conde de Caldagues in command of the blockade, and gave him 4,000-5,000 of the local mountain militia and 2,000 regular infantry to defend a line up to fifteen miles long. Duhesme was still able to send out large columns to gather supplies, but they always ran a risk of being destroyed – the last such column was sent on 12 October, and was caught at San Culgat while attempting to make their way back to the city.
It was during September and October that the Spanish missed their best chance to capture Barcelona. French reinforcements were on their way, but were too far away to intervene, while Duhesme had no more than 10,000 men in Barcelona and was outnumbered by at least three-to-one, while the population of Barcelona was ready to rise against the French at any moment. Unfortunately Del Palacio was not up to the task, remaining inactive at Tarragona, until eventually the Junta of Catalonia had him replaced by General Vives, previously the commander of the garrison on the Balearic Islands. He took command on 28 October. He was a little more active than Del Palacio had been. On 6 November he moved to the Llobregat River, just to the west of the city, and on 8 November even attacked the French outposts. He then remained inactive until 26 November, this time forcing the French to withdraw within the walls of Barcelona.
By that date the best chance to liberate Barcelona had passed. Napoleon had begun to form a new army to reinforce the troops in Catalonia on 10 August, but it had taken until the end of October for the last of the forces allocated to this new army to reach Perpignan. On 5 November this force, now 23,680 strong, under the command of General St. Cyr, was finally under way. His first target was the town of Rosas, ten miles inside Spain on the coast road. The siege of Rosas lasted from 7 November-5 December 1808, and gave the Spanish one last chance to capture Barcelona, but once again Vives missed the chance.
St. Cyr was still faced with a formidable task. The coast road to Barcelona had been destroyed by the Spanish guerrillas, while the inland road was blocked by Gerona. St. Cyr did not have enough time to besiege Gerona, and so St. Cyr decided on a very risky move. On 11 December he sent his supply train back towards Rosas, and plunged into the mountains with food for six days, enough ammunition for sixty rounds per man and no ammunition. If he had been forced to fight more than a handful of skirmishes, or more than one major battle, then the expedition would have ended in failure.
By now food was running short inside Barcelona. If Vives had been able to delay St. Cyr for any length of time, then the city might still have fallen, and there were plenty of places on the road from Rosas to Barcelona where Vives’ field army could have held off the French, but once again he failed to move. Only on 12 December, after the French had bypassed Gerona, did he finally dispatch a division under General Reding to Granollers. After a dramatic march through the mountains, on 15 December St. Cyr’s army reached the main road at San Celoni, east of Barcelona. That evening he marched through the pass of the Trentapassos, the last strong natural barrier outside Barcelona. Only now did Vives move, but even now he refused to use his entire army, taking a single brigade to join Reding.
On the morning of 16 December St. Cyr’s army was between four Spanish forces. To its right was a force of miqueletes, under the command of General Milans. Behind it was the garrison of Gerona, which had left the city, under the command of Marquis of Lazan, to follow the French, but they were miles to the north. Between them these two forces contained 9,000 men. Around Barcelona were 12,000 regular troops under the command of General Caldagues. Finally, at Cardadeu was Captain-General Vives at the head of 9,000 men. Only this final force would take part in the decisive battle of Cardadeu (16 December 1808).
That battle ended in a French victory. When news of this reached Caldagues, in the lines outside Barcelona, he abandoned all of his positions east of the city, and pulled back to Molins de Rey, west of the Llobregat River. On 17 December St. Cyr’s army marched into Barcelona, ending the siege. St. Cyr was still not entirely secure, for the bulk of the Spanish army was still intact and close to the city. This soon changed, for on 21 December St. Cyr attacked the Spanish at Molins de Rey, inflicting a second defeat on them and driving the Catalan army away from Barcelona.