The patroness of Castelvecchio di Rocca Barbena is Our Lady of the Assumption, celebrated on 15 August. The parish church dedicated to her stands just outside the village, in its lower part: its first layout is thought to date from the 15th century, as indicated by the dating of the adjoining bell tower and the frescoed lunette above the main entrance; from the 17th century the building underwent a Baroque remodelling.
The village was in ancient times an important fief of the marquises of Clavesana, who founded and developed it between the 12th and 13th centuries, choosing a hill above the town, around the 11th century, on which to build the castle, with a quadrangular structure and towers. With the marriage of Enrico Del Carretto and Caterina Clavesana, daughter of the marquis of Zuccarello, this branch of the Del Carretto family acquired half of the territories of Castelvecchio and Zuccarello and moved their residence there; in 1326, at the start of Enrico's attempt to wrest the marquisate from the legitimate marquis Federico I Clavesana, known as «il Bestiale», the marquisal residence was moved precisely to Castelvecchio castle, which remained its seat from the 14th century. Between 1623 and 1624 the territory was purchased by the House of Savoy, which held it within its duchy until 1672, when, after a long siege of the town and castle by Genoese troops, the Piedmontese state was forced to cede it to the Republic of Genoa: the stronghold, badly damaged on that occasion, passed in 1844 to another branch of the Del Carretto family.
