In the museum, which was established at the beginning of the 1950’s, the collections of the Museo Civico and the Museo Diocesano were brought together to form one complex through a reciprocal integration which highly represents the art from Abruzzo and the value increased thanks to the monumental prestige and by  the remarkable potential the new museum site offered.  The works which include many of the most significant documents of the regional art, from the suggestive icons and wooden medieval sculptures, to the masterpieces of the Renaissance period, such as the processional Cross of the Duomo of L’Aquila, by Nicola da Guardiagrele and the full relief sculpture of S.Sebastiano, by Silvestro of L’Aquila.  They were ordered for the spacious rooms on the first floor in the eastern part of the building which corresponds to the façade.  Later on, on the second floor, a selected series of works from the XVI century to the XVIII century were set up.  In 1975 the museum, as a preservative storage depot, attained the outstanding legacy left by the Marquis Francesco Cappelli, qualified by a remarkable nucleus of paintings by Mattia Preti.  The archaeological section, which comes from the Museo Civico, was set up in the south-east bastion: the first nucleus of today’s collection is from a donation of the fund set up, with passionate effort by Prince Francesco Caracciolo, in his palace in Barisciano, towards the middle of the XVIII century.  Other important archaeological findings come from the excavations which were carried out in the 19th century by Antonio De Nino and Nicolo’ Persichetti, above all in the area of the ancient Amiternum.  In 1926 the archaeological findings from Alba Fucens and Guardia Vomano were placed in the “Forte”.  Next to the so-called “Calendario Amiternino”, of exceptional importance, there
 are pieces of remarkable interest:  the reliefs with a “Cerimonia funebre” (funeral ceremony) and “Ludo gladiatorio” (a gladiator game), a sepulchral cippus in the shape of a snake and a miscellany collection of commemorative and funerary epigraphs.
In the north-east bastion the impressive archaeological fossil finding was reconstructed.  It was found near Scoppito in 1954.  In the last few years the museum has been subject to a general and outstanding restoration of the museum’s patrimony, of the revision of the exhibitions and of the remarkable development of the museological structures.  This has been made possible thanks to new lighting and air-conditioning systems and to a favourable and valid system of grants and didactic services.