Five hundred years after the construction of the castle of Mula, which was ordered to build the I Marqués de los Vélez, Pedro Fajardo Chacón, as a result of his expulsion from the town during the communal uprisings of the kingdom of Murcia. The fortress, a work of masonry, built on the old Andalusian citadel, has a novel construction in the southeast of the peninsular from the point of view of the multi-aesthetic. The conservation of documentation related to its construction between 1520 and 1531, allows us to approach the work of the stonecutters and master gunners.