The small church of St. Nicholas was most likely built in the first or second decade of the 13th century by the Pisans at the foot of Quirra Castle Mountain. It represents the only example in Sardinia of a Romanesque building made entirely of terracotta bricks. With a single nave, the church, simple and refined in its appearance, has a rectangular floor plan with a semicircular apse.
The facade has a round-arched portal, and is ornamented, as are the sides of the building, with a sequence of hanging arches; the top is topped by a ribbed bell tower with an ogival light.
There are also two single-lancet windows on the sides of the building. Also of the same type is the opening that illuminates the apse, characterized by a spherical covering cap of which there are no other examples in Sardinia and Tuscany
