Between 1372 and 1375, about two centuries after the town was founded, the community of the Borgo decided that a new church should be built inside the walls, up against the western section.
A new church acquired the status of parish church and replaced the original Church of San Biagio set outside of the town walls which stood on the opposite bank of the river Aquila, and had originally been dedicated to the greatly venerated bishop and healer of Sebaste in Anatolia.
The medieval church was divided into a nave and two side aisles and was covered with a wooden roof. In the 15th and 16th Centuries vaulted ceilings covered the apsidal chapels as well as the ones opening out on to the right hand side.
In 1634, the general council of the Borgo chose to re-design and re-construct the existing church so that a new, larger, baroque church has now replaced of the older medieval one.
This rather grand baroque building, designed by the Finalese architect Andrea Storace and continued by his assistant Antonio Sanguineto in 1650, was completed to first fix building level in December 1659 and consecrated in 1690 amidst great hardships and self-imposed taxations from the congregation.
The façade which is divided into three parts and still incomplete, blends in with stylistic traditions from the 15th Century, which were quite different from the artistic views held by craftsmen working on baroque building sites.
The interior of the new church is traditionally divided into a central nave and two side aisles separated by large pillars, with an ample presbytery or chancel where the alter stands and which is only open to officiating clergy.
The central nave is covered with a large single-barrel vaulted ceiling, while the aisles are covered with a ribbed vault separated by arches. Several small chapels open up outwards from the side aisles.
In keeping with Ligurian traditions, the transept, which is the part of the building where the nave and presbytery meet perpendicularly to one another, is the nerve centre of the building. In this church the transept is surmounted by a large dome placed on top of a tall octagonal base, called drum.