According to legend, on July 17, 1490, in the midst of infighting among local families in Panciacci and Cancelleri, some people saw blood dripping from the forehead of a fresco of the Virgin Mary painted on a chapel, which was interpreted as a sign of the Virgin suffering from the bloodshed in the area. The miracle was confirmed by Bishop Niccol Pandolfini, and important families in Pistoia decided to build the sanctuary to honor the Virgin. The construction of this great building was completed in the year 1569, and since that time tens of thousands of visitors visit the church every year.