The Abbey of Casamari owes its name to Caio Mario, from the Latin House of Marii, the famous Roman consul born right here and it is built on the ancient Roman city of Cereatae. It is a jewel of Cistercian architecture and National Monument.
Probably everything stared with hermits who went to live in the ruins of the Roman city around one thousand, when the barbarian invasions had destroyed the socio-economic system, especially the areas in the plains and close to the connecting roads. The inhabitants of the plains had in fact all taken refuge in the hills inside castrum, fortresses or castles. Probably this was one of the centres founded by San Benedetto and was established by San Domenico da Sora.

The current complex was largely built, thanks to Pope Eugene III , after the arrival of the Cistercian monks in 1140 who were already present in the area, precisely in the Abbey of Fossanova. The Cistercian order was founded in Burgundy in 1098 by St. Robert of Molesme, a Benedictine not understood for his desire to renounce riches and he was killed by his brothers. After his death his dream was realized by Englishman Saint Stephem Harding and Saint Bernard from Chiaravalle.

The abbey church was built between 1204 and 1217 according to the mystical style of the order and was consecrated by Pope Honorius III of the Savelli family of Albano with a major event in which the counts of Ceccano also took part. Frederick II of Swabia had passed here several times and his chancellor was appointed abbot.
Over the centuries the life of the abbey has seen history flow throughit, including the looting of the Napoleonic troops in 1799 and the fire of the Piedmontese in 1861.

For a period, it was managed by the Trappist friars.
To the abbey is annexed the State Library, founded on that of the monks, a school, the archaeological museum, and the pharmacy for the sale of liqueurs and medicines produced by the monks.
Much of the complex can be visited and in the summer it hosts concerts and operas.
You enter the abbey complex through a guest house, with a large portico with gothic arches closed by gate,s leading to a garden with an uphill path at the end of which is the church. Part of the monastery buildings also overlooks the garden. Concerts and cultural events take place in this space.

You enter the church through a large portico with three arches, a round arch and two lateral gothic arches, corresponding to the three access doors to the three naves. The main door has a rich medieval decoration and a finely worked stone bezel of particular beauty created by the Canonica. The rear facade is decorated with an important alabaster rosette.
The church has the classic Gothic style of the Cistercian churches and dominates the light stone of the pillars and the ribs of the ceiling. Stone and white plaster are the essence of this abbey. The altar is housed in an elegant eighteenth-century canopy donated by Pope Clement XI.

Next to the church is the monastery built around a cloister where the four corridors that surround it have 4 arched openings and mullioned windows towards the garden with the central well. Each column of the mullioned windows ends with a capital carved in an original way. The chapter house and the refectory are perfect examples of Cistercian architecture.
In the other buildings there is a precious library and the archaeological museum with all that has been found in the area starting from two fossil tusks of a prehistoric elephant. Here are also paintings of the school of Raphael, of Annibale Carracci, of the Serodine, of the Sassoferrato, of the Solimena, of the Siciolante.