Legend tells that in March 1621, the young Sante Bevilacqua looking for hops in the area around the hill of Galloro, near Ariccia, stumbled upon a rock of granite in the ditch of Monticella Piccola which had the face of the Virgin painted on it. Trying to free the rock from the briars and thorns, he set fire to the undergrowth. However, when the flames reached the rock with the Virgin, the fire miraculously went out. Worship of Our Lady of Galloro is dated back to this occasion.
However, it seems that worship in the area could have been older, as a 18th century source relays information from several people in 1623 that there had been miracles by the Virgin for the last 100 years. Furthermore, that very image of the Virgin dates to the 10th century, it was probably painted by the monks of the Order of St. Basil in Grottaferrata who owned the Castle of Ariccia during that time.
From then on, there was a series of extraordinary events in Ariccia: on the day of St. Apollonia, 9th February, 1622, a solemn mass was being held in the collegiate church when it started to rain heavily. Lightning flashed, hitting several people who then presented signs in the shape of the stars that can be found decorating the image of Our Lady of Galloro. It was a miracle and interpreted as punishment for the lack of devotion shown to the newly refound image. Therefore, various festivities were organized to celebrate the Virgin and St. Apollonia became the town saint.
From that moment on, the Virgin communicated with the people of Ariccia through lightning. During the discussions held in 1624 over the site for a new sanctuary in her name, the Virgin flashed lightning on a clear day. The lightning fell on what is today the site of the Sanctuary of Our Lady of Galloro.
1n 1663, the church was completed and the image of the Virgin was to be taken to its new home. All the trees lining the great procession, of about 30,000 participants, bowed in homage to the icon and stayed inclined in this way until they were cut down many years later.
On 8th December, the Feast of the Immaculate Conception, the image of Our Lady of Galloro is still a protagonist in the “Festa della Signorina”. A young girl from the village (in the past, it would have been an unmarried member of one of Ariccia's wealthy families who would then pay for the festival) is chosen to lead the two processions that take place in the morning and the evening. At the end of the day, the 'Signorina' (miss) symbolically offers the image of Our Lady of Galloro to the girl chosen for the following year.