dedicated to Our Lady of the Annunciation, the Collegiate Church stands on the main street, in an intermediate position between the ancient village and the Palace of the Princes. Built between 1480 and 1485 and consecrated in 1486, was built at the behest and at the expense of innocent Fieschi, replacing as parish church The oldest church of San Teonesto.
The inside, majestic and solemn, preserves numerous works of art. A chapel preserves the opera more precious here guarded: The Black Madonna of Masserano or Salus Infirmorum. This is the work that is currently most ancient present on the territory of Masserano, dating back to the second half of the 14th century (the tradition wants even hand of San Luca) and subject to strong popular devotion for its powers of wonder-working. Transported from the church of San Teonesto at the Collegiate Church in 1802, is today located in a chapel of the left nave, built on a project by Edoardo Arborio Mella.
In the presbytery are instead located two tables: the Madonna on the throne with Saints Jerome Giovenone (1520) and the Madonna of the Rosary of the Son Raffaele, work of 1584. The statue of the Madonna Immacolata coated with gold leaf is instead the work of Felice Cassina in 1697.
In the nineteenth century the church was further enriched with works of Ferdinando Rossaro, artist neoraffaelita vercellese friend of Arborio Mella. His are the fourteen stations of the Via Crucis (1885-1888) and the decoration of the cupola with the four Evangelists.