Bastione Imperiale (Bastione di S. Anna). Bastions were the basic elements of the fortifications in the former fortifications. They protected the city, incl. against pirate raids. Their construction was closely related to the development of firearms. Fortifications of this type appeared in Italy in the 16th century. The reason for their construction was the development of heavy fortress artillery. Big guns on long tow trucks could not be placed on walls, or even on towers erected so far, due to their own dimensions and the force of recoil.