At the foot of Mount Pietramarina, the Romanesque church of San Giusto (408 meters above the sea level), according to local tradition founded by Cistercian monks or Cluniac between the eleventh and twelfth centuries, was restored in the second half of the twelfth century.
The building has “commissa” cross plan characterized by a tall, narrow nave punctuated by half-pillars and arches, a transept with elevated crypt, accessible only from the outside, covered by cross vaults supported by low pillars, and three apses with conical roof, typically thirteenth century, and a double row of mullioned windows.
The exterior of the church, built with the use of large blocks of sandstone, shows on the arches of the portal and mullioned window of the front inserts an alternating white marble and serpentine. On the left side of the building, separated from it by a narrow corridor, there is the bell tower, perhaps dating back to 1200 and modified in the nineteenth century.
For more: C. Cerretelli, Prato e la sua provincia, Prato 2003, p. 359 sgg.