In August 1813, the French Imperial Army finally withdrew from Tarragona.
The Napoleonic governor general Bertoletti and his soldiers had occupied the city since its capture in 1811 and had over a two-year period endured such things as; attacks by the Spanish guerillas, a permanent naval blockade by the British Royal Navy and a siege carried out by 16,000 allied soldiers. More recently, a larger allied army had arrived to surround the place again with a total of 25,000 men under the joint command of generals sir William Bentinck and the Duque del Parque.
The night that the French eventually abandoned the city, sergeant Norbert Landsheit, a foreign hussar attached to the British army was resting just beyond the heights of Salou, some ten kilometers to the west. Although the scouts of this advanced guard were vigilant at all hours, nothing had prepared them for what was to come:
“On the night of the 18th, an explosion took place that shook the very earth beneath our feet. The sound was louder than the loudest thunder; and the effect upon all living and dead substances, within reach of its influence, resembled that of an earthquake. We were utterly at a loss to conjecture to what cause the event ought to be attributed and put to one another a thousand questions which nobody could answer.”
At the same moment in the village of Brafím some eighteen kilometers to the north, Doctor Bosch I Cardellach noted in his diary that: At 10 o’clock they blew up the mines placed by the walls and forts of Tarragona with such a thunderous sound that on two occasions it seemed to me that the mountains four hours distant from where I am, literally trembled.
For the next few hours until well into the morning, twenty-two mines were detonated by the French, causing massive destruction at various points of the city. The first had been set off in the mill in the port, followed by another in the fort of San Juan. Later it was the turn of the Cervantes fort and the old roman Pretori tower. The medieval castle called the Patriarch, situated beside the Cathedral, was in turn reduced to rubble by a tremendous explosion. Father Pedro Huya, who had helped evacuate the civilians, explained that:
“It made the most calamitous noise and made the very ground under our feet shake. We saw the fire and knew by this that the most robust monument had ceased to exist, causing us the feelings that one can only imagine.”
Twenty-six neighboring houses in the adjoining Mercería street disintegrated, leaving a pile of rubble one hundred and seven meters long which blocked the way from Ventallols street to the corner of Calle Mayor. Even part of the medieval vaults was demolished.
Chance would have it that just one of the mines, the twenty-third, consisting of various rows of barrels of gunpowder placed in front of the Saint Magí chapel, failed to explode. Its fuse, which today is displayed inside the said chapel, having mysteriously gone out twice.
“There were around twenty barrels of gunpowder. In the second row there were eight barrels each with a hand grenade placed on top, and in the space between there were sacks full of gunpowder. One, which was fifteen palms long by three wide formed the third row in which was embedded the fuse.”
By strange coincidence, this mine, the one placed in front of the Chapel dedicated to Saint Magi, had failed to explode, the fuse having gone out in the early hours of the 19th of August, the very day of the patron Saint of Tarragona, Saint Magí.