Oratory of the nativity of San Carlo. On a picturesque hillock, which rises above S. Mamete, is the small and graceful temple in an elegant Ionic style with an octagonal plan, which seems to have been built by the younger brother of Pellegrino Pellegrini, Domenico Tibaldi of Puria. When Carlo Borromeo was sanctified in November 1610, the Valsoldesi, in gratitude for the good he had received, wanted a chapel dedicated to the new saint to be erected in all the churches of the valley (missing in those of Oria and Albogasio) and that they asked for more rich people built a small temple in a pleasant position. It is said that during the second visit (1582) that St. Charles made to Valsolda, when going from San Mamete to Loggio, tired, he placed a hand on that rock where the oratory stands today. Tradition has it that in the spot where the saint had rested his hand, a cross, once clearly visible, remained imprinted as a souvenir.
Inside the oratory also in Ionic style as an altarpiece is a canvas representing the baptism of St. Charles. The curate of San Mamete, Domenico Pozzi, who wrote the report of the plague of 1630, writes that in that year a procession was made on the feast of San Carlo, in which the relics of the saint were brought with those of other saints, donated by he archbishop of the time, Federico Borromeo, at the oratory of the Nativity of San Carlo sopra San Mamete.
(extract from the volume: "Valsolda", Tip. Arcoveggio, Bologna 1995)