The first attestation of the name "Casulae" is found in the Memoratium of Abbot Bertario, held in the Chronica Monasterii Casinensis. This testimony dates back to a period before September 4, 833, when the abbot was killed. The primitive settlement (7th or 8th century), located between the present church of Sant'Agostino and the road of San Salvatore, had a housing conformation defined as vicana (from the Latin vicus = suburb), and was built on the edge of the ancient tratturo (sheep track) for the migration of flocks from the mountain areas in the territory to the plain of Casoli, at Piano del Mulino and Piano delle Vigne, giving rise to a phenomenon of short-range transhumance. In the first century, Casulae had expanded to become a castrum, that is, a village. It is certain that the flourishing of Casulae in those centuries was due to commercial reasons. It was not, in fact, a closed community, but was integrated—via the road of San Salvatore—into the road system for the transport of goods from the Aventine towns to Anxanum, where famous fairs were held, and to the towns on the Adriatic coast. Another thesis, which is not insignificant, states that the hilltop was inhabited as far back as Roman times. In any case, the first permanent settlement of Casulae, or Casoli, on the hilltop covered entirely by woods, was made up of charcoal burners, who obtained their raw material from the holm oak trees on the southern side of the hill and the black hornbeam on the western side. The two species are suitable for the production of charcoal for sale.The time when the village moved completely to the hillside is not known. Casoli had its own feudal history. The peculiarity is that traces of feudalism can be found in Casoli society until the first half of the 20th century. After the Lombards, with the Norman conquest, the Teatine county was dismembered and Casoli became part of the county of Manoppello (around 1150). Civic history was linked to the chain of possession of the fief of Casoli by the great vassals, such as the Orsini and Colonna families, to name but a few. Starting with the Angevins, it followed the fortunes of southern Italy until the Unification. After the plague of 1630, Casoli was down to 900 inhabitants. The local microcosm was characterised by a demographic and economic explosion as part of what was the European Demographic Revolution. Indeed, from 1750 to 1807, there was an increase in population from 1,764 to 4,834 inhabitants. The further population growth of around 1,000 residents until 1861 testifies to how Casoli had become a socio-economic magnet following the concentration of services in the village. The political leadership of the Aventine Territory would strengthen over the centuries until the beginning of the crisis in the second half of the 20th century. Among the most relevant events are the bloody revolution of 1799 by the popular masses, opposed to the French invasion, and the sad phenomenon of brigandage, which ravaged the area with thefts, kidnappings, and killings of unprecedented violence. Casoli, with its extensive territory, has always had an agricultural vocation. To this day, the high percentage of utilised agricultural area is proof of this. Derurbanisation and the persistence of poverty caused a large number of farmers and farm labourers to leave their home country and emigrate to America (late 19th and early 20th century). In the Giolittian era, the community improved its conditions from a state of backwardness and analphabetisation and embarked on the path to civil progress. In 1906, the line to bring electricity to Casoli and street lighting in the town centre were built. In 1913, the urban aqueduct was built, with intake works from the springs at high altitude on the Maiella, and in the same year the first train arrived at the railway station.

This area, formed by the Square, the Memorial, the former Municipal Building, seat of the municipal administration, and a part of the Palazzo Tilli with its outbuilding, recalls a piece of the history of Casoli, inserted in the wide scenario of the Second World War. On June 10, 1940, from the balcony of Palazzo Venezia in Rome, Benito Mussolini announced to the Italian people the entry into the war of Italy on the side of Hitler's Germans. The first sad taste of what the conflict would be for our country came, as was obvious, with the call to arms of our fellow citizens. The Casolani found themselves, instead, facing an unforeseen contingency connected to the beginning of hostilities: the establishment in the country of a concentration camp for internees. On January 27, 2022, the administration inaugurated a Memorial in memory of the Jews subjected to internment, as a result of the brutal racial laws of the Duce, and of the Slavs, considered politically dangerous after the invasion of their land by Axis troops. The Jews lived in the Casoli Camp from 1940 to 1942 and the Slavs from 1942 to 1944. The Memorial Square and the adjoining Memorial were built in an area close to the internees' quarters. The Camp was originally formed by two main buildings: the cellars of Palazzo Tilli (with a capacity of about 50 seats) and the premises on the ground floor of the former Municipal Town Hall with a capacity of about 30 seats. Shortly after the internees from the cellars were transferred to the annex of the building, then also used as a room for theatrical performances, cinema and parties. A total of 108 Jews and 110 Yugoslavs. Ten Jews who lived in the Casoli Camp, deported by the Nazis to the extermination camps, died in the gas chambers (nine in Auschitz and one in the Risiera di San Sabba, the ancient San Sabba rice bowl). The complex is a point of reference for our community and for visitors, because it too, in its small way, contributes to keeping the memory of the Holocaust alive so that it does not get lost in the fog of oblivion.

The reconstruction of the ancient sixteenth-century village on the plan of today's Casoli, with the identification of the current toponyms (at the time the system was not in use), was carried out on the basis of the Regesti by Nicola Fiorentino combined with the results of the inspections carried out on the ground, during which some medieval vestiges survived to this day were taken as reference. The perimeter of the map of the Casoli of the sixteenth century is quite adherent to the real situation. The town walls were formed by "Inforzi" (Inforce walls), so called in the Regesti. They were not defensive works as such, but rather supporting perimeter walls that enclosed the village and, at the same time, could be used to outflank the enemy during possible assaults from outside. The location of the gates, small gates and other architectural elements coloured in blue reflects the exact position where they stood. The "Torrone", so called in the notarial acts, was in fact a turret or a tower, probably of defense. Three of them can be visited and which, in their present state, do not have any constructive features that suggest a military-type structure. The peasants lived within the village. They went out at dawn to cultivate the fields and returned to the sunset through the three main doors, called Porta Carrozza, Porta Cencio (the most used) and Porta da piedi, or the secondary entrances, of reduced dimensions, called "Portelle" (Small Gates). Already since then stood, next to the Tower, a part of the Ducal Palace built by the Orsini Family, used as warehouses for foodstuffs, stables and housing and the central nave of the Church of Santa Maria Maggiore probably less long than the current one. Not far from the Tower, in today's Via Giannino, there was the church of San Pietro (Year 1173). It should be noted the presence of vegetable gardens within the walls and aquifer veins of very modest capacity. It is preferable to start the visit of the village from Via del Tempio (see green arrow), stop at the Church of Santa Maria Maggiore and continue, going up the Arco del Purgatorio (Arc of Purgatory), up to the Castle, the final destination of the visit to Casoli. Two alternative routes back to Piazza del Popolo are shown on the map. The first is to descend from the Castle to Piazza Gentile, walk along Via Giannino and turn left onto Via Laudadio to reach Via Centrale, ideally passing through Porta Carrozza. From here you can make a short detour to see the Torrone "A" and then turn back to walk the entire length of Via Centrale, passing in front of Torrone da Sole, to reach Piazza del Popolo. The second route is around the castle to the right-hand steps of the church. From here, take the narrow covered alley on the left, where there is a mural, and, downhill, walk along Via Scalelle and continue along the route indicated on the map, leaving the 16th-century Borgo where Porta da Piedi used to be, to reach Via Roma and then Piazza del Popolo. In both cases, one can spot uninhabited old stone houses, interspersed with others that have been renovated, especially by people from northern Europe, to immerse oneself in the atmosphere of times gone by. Once you arrive at Piazza del Popolo your pleasant visit to Casoli ends. The mayor, the municipal administration and the entire community hope you enjoyed your stay in our town.