The patroness of Bonassola is Saint Catherine of Alexandria, celebrated on 25 November. The parish church dedicated to her, in the main village, was built according to some sources in the first half of the 16th century, but almost entirely transformed in later centuries, particularly during the Baroque period; it was consecrated on 8 July 1668 by the bishop of Luni, Giovanni Battista Spinola, and holds inside several sculptural and pictorial works, including paintings by the painter Pietro Costa.
The first official mention of Bonassola dates from a document of 29 April 1269, which mentions the local church of San Giorgio di Reggimonti; an even earlier citation, from 18 March 1154, appears in a document of Pope Anastasius IV confirming to the bishop of the diocese of Luni the dependencies of the parish of Ceula, including the church of Scernio. Archaeological excavations carried out between 1959 and 1960 by Leopoldo Cimaschi near the locality of Chiesarotta brought to light the remains of the ancient church of San Giorgio, also establishing human presence well before Roman colonisation. On 12 December 1561 the report requesting the building of Bonassola Castle was submitted to the Genoese Senate, which decided on its construction on a hill behind the village.
