The medieval church of San Lorenzo in Orco initially rose in Romanesque style on the hill where the Orco castle rose, mentioned as the “castrum Orchae” in a 1162 diploma of emperor Frederick the 1st of Swabia. The first traces regarding the church date back to 1195, when the marquis Enrico II Del Carretto donated, for the redemption of his sins, the tithes on the vines, mills and buildings for the production of canvas set in the valley floor of Feglino.

The cross shaped single-lancet window, made out of a single block of stone, originally belonged to the Romanesque church and was then reused in the late medieval church.

In the 15^th century the church was rebuilt by reusing elements of the former building. It had a polygonal apse that was constructed directly on the rocky cliff. On the left side a small bell tower was built with small arches, bezels and brick mullioned windows with columns. On the right side of the nave, commissioned by Bartolomeo Fresia at the end of the 15^th century, a series of devotional frescos with the image of the Virgin and Child, of saints and St. George in the act of killing the dragon were painted.

The inner vault of the apse was decorated around 1571 with frescos depicting the Eternal Father between the four Evangelists painted in the lunettes.

In 1674 the title of parish was moved to the church dedicated to Nostra Signora delle Grazie that had recently been built in the locality of Colletta and then dedicated to San Lorenzo. The ancient church, now called San Lorenzino, however, kept its role in the devotion of the local population.