The main altar was made between 1853 and 1858 at the same time as a series of renovations in the presbyterial area.
The altar has a white marble table and is not placed against the wall. The tabernacle – added in 1866 – takes the shape of a classical temple surmounted by circular dome on eight columns, a style in accordance with the neoclassical style typical of the second half of the 19th century.
Dating back to the 1950s, the small white marble riser flanking the central tabernacle contains six bronze medallions. Each medallion depicts a patron of the church: Saints Firmus and Rusticus, the Eucharistic symbol of the pelican feeding the little ones, the Madonna del Rosario, Saint Blaise and the Paschal Lamb.
On the side walls of the altar there are two white stone statues depicting the announcing Archangel Gabriel on the left and the Madonna on the right. Both statues date back to the end of the 1600s and are from the hands of brothers Orazio and Francesco Marinali.
The altarpiece of San Carlo Borromeo Adoring the Trinity is located in the apse and was created towards the end of the 1600s.
