After the violent bombardments with heavy cannonballs by the army of King Louis XII, in an attempt to help the Florentine troops during the siege of Pisa in 1503, the walls of Pisa were heavily damaged. It was Cosimo I de’ Medici, in 1543, to start an impressive restoration of all the defensive structures of the city, including the area in front of the ancient convent of San Silvestro. Architect Nanni Unghero was appointed with the project and designed an embankment, which was subsequently fortified. The works ended in 1557. The name Barbagianni (Barn Owl) seems to derive from the presence of the birds in the area. The whole area is now a beautiful public park, called 'delle Concette',for the past presence of the nuns of the Immaculate Conception.The church of San Silvestro, in the homonymous square in front of the bastion, was founded in 1118 for the Benedictine monks and later donated to the nuns of San Domenico. Grand Duke Pietro Leopoldo dei Lorena turned the monastery into a Conservatory for noble girls. In 1812, Napoleon Buonaparte inaugurated here the academic college, known today as the Scuola Normale Superiore. The façade is from the 18th century, but the back still shows its medieval aspect, with ceramic basins from the 12th century (the original ones are in the National Museum of San Matteo).