In just under 28km2, the territory of Castrocielo, which is located on the southern border of Lazio, or the cultural region known as Ciociaria, is immersed in the Liri Valley, on the slopes of the Mount Cairo.

Castrocielo has been witness and protagonist of important historical events and is the birthplace of illustrious people who have helped shape its cultural identity.

The first traces of civilization date back to the Volsci (V sec. a.C) and the Sidicini (IV sec A.C) of which the town preserves notable traces, such as the funeral arrangements restored and museums in the dedicated spaces in the Town Hall.

The ancient city of Aquinum has the Roman roots of Castrocielo. Aquinum, located on the ancient Via Latina, a colony at the time of Ottaviano, Marcantonio and Lepido, was a thriving tourist-spa town, located between Rome and Pompeii.

The start of the archaeological excavations in 2009 highlighted from the beginning the extreme importance of the site, bringing to light a thermal plant among the largest in Lazio, characterized by a remarkable decorative apparatus (mosaics, stucco, plaster, polychrome marble).
Testimonies of the ancient greatness of Aquinum are the statuary and the conspicuous monumental remains reached up to our days of the urban area, among which Porta Romana, that is the western gate of Aquinum under which passed the Latin way; the Torre Quadrata that, built in large blocks of travertine, was one of the towers that constituted the defense system of the city; the Temple Major possibly dedicated to Ceres Elvina or lno Pupluna or Luno Regina Populonia, also known as Capitolium, whose structure is grafted on a pre-existing pre-Roman era, possibly converted to a Christian church ; the building Absidato or Temple of Diana of which there is a semicircular apse; the theater, visible along the Via Latina, of which have recently been brought to light not only several architectural elements related to the decorative apparatus, but also the remains of a barrel vault that supported the above order of bleachers; the Arch of Marcantonio (whose attribution originates from a passage of the Cicero Filippiche) which represents one of the oldest examples of honorary arch known in Italy; the imposing Pompeian-type thermal complex of the Terme Centrale which is located in the 1st century B.C., partly depopulated around the fourth century and converted into a necropolis between the fifth and seventh centuries AD. C, perhaps in connection with the arrival of Totila and his Lombards, which caused the escape of the aquinenses and the destruction of Aquinum.

The aquinenses, fleeing from the Lombard invasions, populated the "asperrima" peak of Mount Asprano, over the centuries subject, for its strategic position, numerous disputes between the princes of Capua and the counts of Aquino, who gave birth to the father of the church Saint Thomas Aquinas, and then between the latter and the Abbey of Montecassino. These disputes lasted for much of the medieval period.

It dates back to the twenty-eighth Abbot of Montecassino, Mansone, who between the years 988 and 994 had received as a gift from the princes of Capua Mount Asprano, the foundation of Castrum Coeli (the original inhabited modern Castrocielo) on the summit of Mount Asprano and the beginning of the construction of the castle ( il castrum) on the ruins of the pre-existing houses, fortified by the will of Frederick II of Swabia in the thirteenth century. The castle of Castrum Coeli, is not far from the castle of the Counts of Aquinas ( about 1,500m as the crow flies) where Saint Thomas was born in 1225, theological and philosophical pillar of the Catholic church.

After the period of Lombard and Saracen raids, the population began to descend to the valley, in search of easier living conditions and lands to cultivate: part, already in the eleventh century. went down to the North-East, founding first the village of Cantalupo and then the village of Colle San Magno; another part went down instead in the valley to the south, forming the two inhabited modern Castrocielo, one, larger, on the slopes of Mount Asprano "l'Olivastro" and the other north of a moat, which was given the name of Palazzolo by virtue of the remains of a palacium of Roman times around which the same town was built.

The town, initially known by the name of Palazzolo, assumed with the R.D. of 26 March 1863 the name Palazzolo di Castrocielo, modified with R.D. of 16 August 1882 in Castrocielo.
Interesting the genesis of that palacium, according to some theories is attributable to the "Monacato of Villa Euchelia", a former convent of Benedictine nuns, built on the base of a large Roman villa also destroyed under Lombard attacks. At the time of the foundation of the first village of Palazzolo, the structure must have appeared majestic, with fluted columns, for this reason it was probably called "palatium". Over the centuries it became first a monastery of friars, under the control of the nearby Abbey of Montecassino, then a convent. The recent renovation to which it has been subjected, has preserved its original character and as soon as you cross its gate, it is difficult not to let go of that kalendoscopic of suggestions that the place evokes.
Villa Euchelia, today a polycultural center, retains its typical appearance of a convent with a central courtyard. The facade contains two portals with external arches.

In medieval times, when Christianity monopolized culture, the Abbey of Montecassino- one of the most famous monasteries of Christianity, cradle of culture, founded in the sixth century by the same Saint Benedict, place of formation of Saint Thomas- acting like the patrons of the Renaissance, commissioned illustrious artists of the time to decorate chapels and churches, local, including those in the territory of Castrocielo. Of great historical and artistic importance are in fact the frescoes that decorated the medieval Romanesque church of Madonna del Pianto otherwise known as Madonna dei Sette Dolori and the nun of Villa Euchelia. Severely damaged by the bombings of the Second World War, they were restored and placed in the Pinacoteca di San Rocco, located in the homonymous square of the village.

The church of the Madonna del Pianto, was located along the path of the foothill. The church was built in medieval times, on the banks of the picturesque lake formed by the source of "Capo d'Acqua", to offer refreshment to pilgrims and travelers to the Abbey of Montecassino and the Holy Land. Today, in those places, the walkers of the Way of Saint Benedict find refreshment.

The church of Santa Maria Assunta in Cielo, on the summit of Monte Asprano, dates back to the Middle Ages, around 1300. It was built when the two communities had already begun the descent to the valley. The church ensured the ordinary liturgical service to both the community of Colle San Magno and that of Palazzolo, until Castrocielo in 1601, until then owner of the Church of Santa Maria Assunta in Cielo, he brought with him the reliquary to put it in the sacristy of the new Cathedral of Saint Lucia in Castrocielo, as recalled by a plaque placed in the sacristy of the cathedral. The ancient tradition of the "kiss of the Madonnas" dates back to the same period. Or the Monday procession in Albis, when the two communities of Castrocielo and Colle San Magno, clinging to the two opposite sides of Mount Asprano, lead in procession the respective statues of the Madonnas towards the church of Santa Maria Assunta in Cielo, outside of which, the two Madonnas, met and in front of each other, are bowed, remember the common origin, under the Marian seals.

The destiny of Castrocielo and its historical and cultural identity have been linked for centuries to the Abbey of Montecassino. Not least, from the events related to the Second World War, which saw the Abbey at the center of the Gustav line, and Castrocielo, like the Abbey, first occupied by German troops and then bombed by Allied forces. Centuries later, the castrocielesi, once again suffered hunger and destruction and had to regroup in the mountains. To the castrocielese community tormented by the war, in recognition of the "splendid example of spirit of sacrifice and patriotic love", was granted in 2004 the silver medal of civil merit at the hands of President Ciampi.

Castrocielese culture and identity have strong Roman and Christian roots, which pervade its material and intangible heritage. The numerous Roman and medieval monumental remains, the churches and chapels, its saints and illustrious historical figures, the ancient rites, the tradition of the "Kiss of the Madonnas" jealously guarded by the two twin communities in a secular pilgrimage, are strongly evocative of its origins and a strong sense of pride of its roots.
Castrocielo has lived the story as a protagonist and its identity is strong.