Monastic life was started at Trisulti, situated at the foot of Mt. Rotonario, by St.Dominic of Foligno, a great reformer and founder of Benedictine abbeys in southern Latium. In the year 1000, he built a magnificent monastery, most of which still stands.
After two centuries of Benedictine life, Pope Innocent III decreed in 1204 that the abbey and its possessions should pass to the Carthusians, who sent four lay 
brothers there with the task of building a new monastery suitable for their type of monastic life and safe from falling rock. Even today, wire webbing covers cliffs on the side of the road leading to the monastery. In 1211, a new church was consecrated and dedicated to the apostle St. Bartholomew, again by Pope Innocent III.
Since 1947 the monastery has been looked after by the Cistercians of Casamari who carry on their lives interwoven with work and prayer. 
The small group of six monks has given new life to the buildings and grounds, welcoming tourists daily.
On our visit, Don Claudio joyously showed us around. His stories behind the spectacular buildings, paintings and frescoes made the one-hour tour seem like ten minutes. If you have only one monastery on your list to visit, make it this one.