The Church of Sant’Erasmo in Porto Ercole stands in a panoramic position, almost at the very top of the promontory on which the old town is situated, above the Santa Barbara pier, in a setting dominated by the lighthouse and the Rocca Aldobrandesca. Its location, overlooking the sea, perfectly reflects its connection with Sant’Erasmo da Formia, patron saint of sailors and of the town.

The building’s origins are very ancient: the original structure is thought to date back as far as the 4th century, on the site where the choir stands today, to which a small oratory was added in the 7th century. For centuries, the church served as the village’s main parish church, situated within the Sienese walls to distinguish it from another church dedicated to the same saint, built outside the walls.

In the 17th century, the building underwent extensive alterations, taking on its current façade in the simple and unadorned Tuscan Baroque style, characterised by a portal surmounted by a triangular pediment and a small central rose window. The original bell tower, in the Spanish sail-style and dating back to the 14th century, was severely damaged by lightning in the 18th century; the current one was built in 1915.

The interior is divided into two naves: a main nave and a smaller side aisle facing the sea. The ceiling of the main nave is supported by 17th-century wooden trusses, which are still well preserved. With the construction of the new parish church of San Paolo della Croce in the modern village, around the mid-20th century, the church gradually lost its central role, although it continued to be used for services and special occasions.

Behind the church, along a steep flight of steps leading up to the promontory, lie the remains of the Confraternity of Santa Croce, dating back to the 15th century, where a small sanatorium once operated. According to local tradition, it was here that the painter Michelangelo Merisi, known as Caravaggio, was taken in 1610 after being found dying on Feniglia beach. This evocative theory adds a further element of historical and cultural charm to this place, already rich in history.