The ancient Saint Peter’s church has always interested scholars under the historical and artistic point of view. After historians, it was built up in the “castrum” of Capignano in the first halt of the 12th century. At the beginning it was likely a castrensian chapel. The first paper mentioning this church dates back to 1184, when Pope Lucio II recognizes Saint Peter and other local churches, belonging to the priorship of the Cluniac Benedictine monks of Castelletto (Castelleto Cervo) in Vercelli territory. The Saint Peter’s Church is totally absorbed into the ancient Castle. It has the nave and two aisles. The nave is marked with cross-shaped pilasters leaned against the walls, which interrupt at two thirds of height, just where the building was raised in the XIII century. Both small aisles are covered with 18th-century vaults, except for the south half-aisle (close to the apsidiole) keeping a rough XI century cross vault, rare example in North Italy. The inner walls, after an important recent restoration, are covered with important ancient wall-paintings: The Christ Pantocrator is in the upper part of the apse dome; the Apostles, unfortunately partially damaged by two windows, are in the register, and furthermore, a fragment showing the “wild man” is in the lower part of the socle. Other wall-paintings, dating back to the gothic period, are visible on an arch between the nave and the south aisle. They depict Angel Gabriel and our Lady of the Annunciation, while Saint Catherine stands on a pilaster. The outer walls were mostly built with pebble stones from the Sesia River, alternated with salvage bricks of Roman and Medieval age. The three apses, visible in Via Carducci, are decorated with hanging archlets made in baked clay. The owners and uses of this building have been many over centuries, but the most disastrous one happened for sure in 1885, when the laws of the Kingdom of Sardinia forced the requisition of the buildings of the Religious orders. For this reason also Saint Peter of Carpignano, already belonging to the properties of the Bishop of Biella, is first deconsecrated and then sold to privates, who used it with no scruples as cellar and shelter for agricultural means. Today it is property of the municipality.