These accessions of strength raised the force of troops in the besieged town to upward of three thousand.
The next day a case of treason was discovered among the Spaniards in the garrison of Montjuich.

A boy confessed that he had been hired by one of these men to put out all the gun matches, and to throw the priming powder out of the matchlocks that night.

He was told to do this on the weakest side of the works, where the attack would probably be made.
The discovery of this intended treason, following so closely on that at Fort Redonda, excited suspicions of the loyalty of the Spanish Governor of Montjuich, and he was superseded and the Earl of Donegal appointed to the command.

For the next six days the French continued to raise battery after battery around Montjuich.

Lord Donegal made some gallant sallies and several times drove the besiegers from their works, but in each case they returned in such overwhelming force that he was obliged to abandon the positions he had won and to fall back into the citadel.
The Miquelets, of whom there were many in the town, aided the besieged by harassing the French.