The church, dating from the late 11th century, was built on the initiative of Archbishop Daiberto and completed thanks to the generosity of Countess Matilda of Tuscany. The Church is dedicated to Saint Ermolao, the protector of Calci and the Val Graziosa (the area around Calci at the foot of the Pisan Mount), who is traditionally celebrated with a feast at the beginning of August.
The Pisan Romanesque façade is divided by two tiers of blind arches. Decorations consist of geometric motifs that are typical of Pisan architecture. To the left of the church stands the thick, unfinished bell tower, built of stones and bricks. Up high on the same side is an antique head, possibly representing Jupiter Ammon.
The interior is divided into a nave and two aisles by granite columns topped by Ionic and Corinthian capitals.
Interesting items in the church include the high altar built from Carrara marble, the 17th century lesser altars, the Madonna with Child between Saints Hermolaus and Francis, an 18th-century oil-painted altar-piece and a 12th century baptismal font consisting of four basins sculpted from a single block of marble and decorated with reliefs, produced by the school of Biduino.
