It, along with the neighboring Church of the Assumption of St. Mary, are both Swiss heritage sites of national significance.

The hill top was inhabited prehistorically and by the late Roman era was home to the Church of Santa Maria.

[2] The first castle probably consisted of a ring wall that followed the top of the hill and a residential building in the north corner.

In 1480 they sold their headquarters at Mesocco Castle and its associated demesne, including the Santa Maria area, to General Giacomo Trivulzio.

[4] Fragments of the old residence tract are visible on the north end of the hilltop as is a small part of the old ring wall to the west.

The Gothic bell tower is north of the choir and is topped with a Baroque octagonal pyramid spire.

Above the choir, the cherubs hold the coats of arms of Calanca, the Gray League, Grono and San Vittore.

[7] The original high altar, by Ivo Strigels in 1512, was moved to the Basel Historical Museum in 1887.