The building, like most of the buildings in Albenga, is the result of the unification of various medieval housing units. The corner towards Piazza San Michele incorporates the thirteenth-century tower, which has a black stone base in which a slightly ogival door opens; the top, once decorated with Guelph battlements, has been modified to create a smooth decorative band with pillars at the corners that support four marble spheres. The sixteenth-century facade originally had windows with slate frames of which two examples are preserved in the tower; the side facing via Cavour returned traces of medieval frescoes during the restoration of the 1950s; it is instead the internal decoration of the noble floor that makes the building one of the most important in Albenga: in fact it has a vast ornamental apparatus built from the 15th to the 19th century. On the first floor there is a remarkable sitting room which has a large fireplace and finely worked slate portals and marble busts of Roman origin; the ceiling fresco is dated by the family crests between the last years of the century. XVI and early XVII, while the walls have decorative paintings, more recent, with scenes of hunts and battles. The small chapel has frescoes in “grisaille” dated 1600. A part of the frescoes of humanistic inspiration is located on the second floor, where the frescoed band in the room known as "the philosophers" dates back to the second half of the fifteenth century.
The Cepollas, one of the oldest and most conspicuous families of Albenga, known since 1222 and always remained between the city and the territory, achieved wealth and an important role in the Middle Ages. its members, very numerous, held important positions in the administration of the municipality and managed a conspicuous activity in the financial field; fortune made with the trade on the sea and with the lending activities, as for most of the Ligurian families. The Cepollas appear to be by far the wealthiest family in the city, possessing numerous towers and houses. They were enfeoffed by Aquila, Onzo, Alto, Caprauna, Nasino and had the title of count, binding themselves in marriage twice in the 16th century with the Dorias. At the end of the 1500s Prospero Cepolla di Pietro and Bianca Doria, born in 1543 and married to Teodora Costa, sister of Ottavio Costa, a banker in Rome, started major renovations to equip his family with a building that had a representative function, a role that the oldest houses could not play. Prospero, however, was also the last of the Cepollas; the palace, through some passages to the descendants of one of his daughters, was for more than two centuries of the Peloso counts. Finally, in 1947, Dr. Agostino Niccolari, the last heir of the family, wanted in his will to bequeath it to the municipality of Albenga; however binding it to the headquarters of the Ingauna Section of the International Institute of Ligurian Studies which in 1960 constituted the headquarters of the Experimental Center of Underwater Archeology and the Roman Naval Museum.
The Museum, currently being renovated, was founded by Professor Nino Lamboglia in 1950; originally arranged as an exhibition in the Council Chamber of Palazzo D'Aste, following the restoration works in the 1950s, it was housed in Palazzo Peloso Cepolla. On display are the finds of a large Roman cargo ship from the beginning of the 1st century BC, sunk in front of Albenga, recovered during the first attempt at an underwater archaeological excavation carried out in February 1950 with the rudimentary means of the time. In the partial reconstruction of the side of the ship, part of the amphorae of the cargo, which is estimated to have been around 10,000 amphorae, are scenographically placed, as they were on board; There are also many pieces of the on-board equipment, remains of helmets, pottery and part of the boat's planking. The new Roman Naval Museum will be set up in close collaboration between the Ministry of Cultural Heritage and the Institute of Ligurian Studies, and will be equipped with a state-of-the-art multimedia device, capable of reviving the experience of the discovery of the Albenga wreck: which to this day is one of the largest known Roman trading ships.
The building also houses the Ingauno Historical Archive, a complex of private archives of the territory, the ancient fund of the Municipal Archive of Albenga, and the library of the Ingauna Section of the Institute of Ligurian Studies.