The church, proclaimed national monument, dates back to the first half of the sixteenth century. It was erected on the remains of a former Romanic building (Sancta Maria de Egro) of which only the bell tower (eleventh century) and some traces of walling are left.
Outside, more than the front a hut covered with square blocks of serizzo, the high octagonal base of the cupola, with continuous loggia and surmounted by a overhead lantern, is impressive.
The three-naves inside is adorned with distinguished works of art, mostly dating back to the first decades following the consecration of the church, which took place in 1547.
In the chapel of the Madonna delle Grazie, adorned with the traditional symbols of the Virgin and with valuable paintings by Camillo Procaccini, there is the venerated Madonna del Latte (fourteenth century), a fresco coming from the pre-existing church afterwards integrated in the new complex. In the chapels of St Lorenzo and St Bernardo, portraying scenes from the life of the two saints, there are frescoes ascribed to Bernardino Lanino and his sons.
The frescoes of the dome, portraying St Agostino, St Gerolamo, St Ambrogio and St Gregorio spaced out by couples of angels playing instruments, are ascribed to to Cesare Luini, while the frescoes of the apse, celebrating Our Lady, are attributed to Carlo Urbino and Aurelio Luini.
The wooden choir, a 1582 work of Andrea Merzagora of Craveggia (a town of the nearby Valle Vigezzo), is of great worth. Other excellent works are: a finely carved lectern with the symbols of the four evangelists (an angel, Matthew; an ox, Luke; a lion, Mark; an eagle, John), a splendid Baroque pulpit, and the baptismal font surmounted the figure of Christ kneeling while He is christened.
The monumental complex includes also a building dating back to the beginning of the seventeenth century, former seat of the seminary, on the north of the church, and a eighteenth-century ossuary with noteworthy wrought-iron gratings on the south. Some concerts within the well known event "Settimane Musicali di Stresa e del Lago Maggiore" take place here.
