The exterior of this small church consists of a double-sloped frontal with a cornice running the entire length of the facade, dividing it into two sections.
Tarchna, Corneto, Tarquinia
The upper portion is richly decorated with an ornate rose window while the lower portion features the portal, framed by a ring of concentric arches which are bichromatic in macco (a type of stone composed of compressed organic sediment which is typical of the area) and nenfro (a kind of volcanic stone). In the rear of the church there are three apses which are readily distinguishable. Within the church there is a single nave divided into two bays with a single X – shaped pattern on the roof with rounded arches. It is interesting to note that the transept which juts out from the main body of the church was most probably a later addition to the church, whereby the original layout included only a large hall with a single apse.