The patron saint of Petrella Tifernina is Saint George the martyr, celebrated on 23 April. With the arrival of the Lombards, around the 10th century, the cult of the saint was brought to Petrella, to whom the town's first church was dedicated, the one still existing today, the result of various rebuildings over the centuries. The current church of San Giorgio Martire dates from the 12th century, and was declared a national monument in 1901: the Romanesque-style interior is divided into three naves closed by their respective apses, separated by two asymmetric colonnades whose capitals echo decorative motifs similar to those on the exterior; it also houses a richly decorated hemispherical monolithic baptismal font, and a crypt dedicated to the saint.
The town also preserves the Palazzo Baronale: after the fall of the Swabians, it was Charles I of Anjou who claimed the fief, granting it to Pandolfo di Petris Grossis.
