Aqiila, a fortified city of Italy, capital of the province of Abruzzo Ulteriore II., on the Aterno, 56 m. N. E. of Rome; pop. about 12,000. It was built by the emperor Frederick II. in 1240, from the ruins of the ancient Amiternum, the birthplace of Sallust. It was much reduced by earthquakes in 1G88, 1703, and 1706. It has a large number of churches and monastic houses.