Forte Spagnolo The Forte Spagnolo ( Italian for " Spanish fortress " ; locally called " il Castello " ) is a Renaissance castle in L ' Aquila , central Italy . History . In the 15th century , L ' Aquila had become the second most powerful city in the Kingdom of Naples after Naples itself : there were half a million sheep , wool and saffron were exported throughout Europe ; all this unfortunately was lost when the Aquilans , during the war between the French and the Spaniards for the throne of Naples , sided with the French . In 1504 Aquila the city was occupied by the Spanish conquerors . Then in 1527 the French recovered the city with the support of the citizens and the surrounding town . One year later Viceroy Philibert of Orange , ruling for King Charles V of Spain , finally defeated the Aquilan rebels and ordered the city to build a fortress in the highest spot North of the city , exactly where in 1401 King Ladislaus had built a garrison to control the unruly and rebellious Aquilans . The project was entrusted to a Spanish architect , Pedro Luis Escrivà , an expert of firearms , who had begun to build Castel Sant ' Elmo in Naples . The discovery of gunpowder obliged to new methods of defensive construction . Escrivà was in charge of the project for 2 years , leaving the task to Gian Girolamo Escribà . In the following 30 years the heavy taxes necessary to build the fortress impoverished the city , which in 1567 begged the Spaniards to stop the construction ; the Royal Court granted the request , and works were interrupted , so parts of the castle were never completed . The fortress had cost an enormous sum for the times , and Aquila was obliged also to sell the thick silver case containing the body of St . Bernardino of Siena . The fortress , which had been built not to defend the city , but to control it ( its cannons pointed to the city ) and to be a completely self - sufficient structure , was never used in a battle . Architecture . Escrivà planned a giant fortress , made of four bastions connected through mighty walls , 60 meters long , with a thickness of 30 metres at the bottom and 5 meters at top . The walls were surmounted by massive merlons , with openings for the archers and the long - distance cannons . All around the fortress was a ditch ( never filled with water ) 23 meters wide and 14 meters deep , aimed at defending the foundations from the enemy ' s artillery . Escrivà did not forget any detail : the slanted walls would reject enemy fire to the sides ; each bastion consisted of two separate and completely self - sufficient environments - called " case matte " - almost independent garrisons on their own . Also the aqueduct to the city was deviated so as to supply the fortress first of all , and in case of rebellion block the water supply . Moreover , Escrivà planned a special anti - mine corridor , a kind of empty space between the outer and inner walls which could be walked only by one man at a time ( and which can be visited today ) , aiming at defending the castle in case of explosion in case enemy soldiers excavated tunnels to leave mines at the foundations . A whole hill was leveled down to supply the white stone necessary for the fortress , while the city ' s bells were melted to make the cannons . In 1798 the citizens fought against the French who had invaded Italy , attacking , in vain , the fortress . From then on , the building was used as a prison . After 1860 it became a military headquarters , and in the Second World War was occupied and damaged by the Germans . Between 1949 and 1951 the castle was restored , and chosen as the seat of the Museo Nazionale d ' Abruzzo .