the evangelization of Bomarzo must go back to a period very ancient if already in the VI century possessed a bishop and a chapter. The historian Flavio Biondo assumed that even the Pope Sabiniano, pontiff from 604 to 606, was born in Bomarzo. From this we can infer that already in the Byzantine era the village was also provided with a church of a certain importance, built in the style of the early Christian. In the Carolingian age the Duomo was probably modified, as demonstrated by some architectural elements dating back to the VII-IX century.
The current structure dates back to the XV century and reflects the style of Filippo Brunelleschi who in that period worked in Florence. In 1546, under the loggia of the facade was dug a pit for the benefit of the Community bomarzese. The work was commissioned by the deceased Lord of Bomarzo John Corrado Orsini, was completed by him daughter-in-law Giulia Farnese while her husband, Pier Francesco said close, was in Germany to fight for Charles V. Further modifications were made in the seventeenth century, when they were completed the facade and the stair access.
The facade, from sober lines and simple, is characterized by an elegant staircase in horseshoe, dating back to the XVII century. Other highlights are the doors, refined from the lacunar classical style, and pinions inserted in the second order, contemporary to the tiers of seats.
The interior of the church has three naves divided by pillars in peperino, and fits in well with the austerity and elegance of the exterior. In the high altar there is inserted a valuable altarpiece depicting Saint Anselm that supports the town of Bomarzo and addressed to the Virgin of the Assumption, to whom is dedicated the duomo. Under the altar are preserved the mortal remains of the saint himself.
The bell tower, erected on a structure of Etruscan origin, is built in blocks of peperino. The only special feature is represented by a Roman tombstone depicting a man and a woman, which was incorporated in the structure of the bell tower.