Before the Fortress was even finished it became out-dated. In the 1860s there was an important evolution in artillery technology. Instead of the old-fashioned muzzle-loading cannons (front loaders), powerful breech loading cannons (rear loaders) were designed, which had rifle boring (a series of helical grooves in the interior of the barrel) which made the projectiles fire with more spin, improving their accuracy.

This meant that the island’s defence system had to be reconsidered. Instead of mounting all the cannon emplacements within the fortress, a second development phase was initiated (1896); a series of coastal batteries were set up away from the walled fortification. These batteries took care of the remote defence of Minorca’s coastline, with their powerful projectiles capable of detaining all types of enemy battleships.