It comprises the provinces of Teramo (population in 1901, 307,444), Aquila (396,629), Chieti (370,907) and Campobasso (366,571), which, under the kingdom of Naples, respectively bore the names Abruzzo Ulteriore I., Abruzzo Ulteriore II., Abruzzo Citeriore (the reference being to their distance from the capital) and Molise.