The origin of the Sanctuary goes back to the year 800 A.C., initially consisted of a small church dedicated to St. Maria Eremitana; the first guests, up to the year 1320, were the Basilians, then it passed to the Franciscans who dedicated it to St. Maria delle Grazie, until 1348 when the plague downsized the Order.
According to tradition, the "Holy Thorn" arrived to Petilia Policastro thanks to Father Ludovico, a grandson of the venerable Dionysius Sacco, Bishop of Reims, who in 1498 had received it as a gift from Jeanne de Valois, wife of King Louis XII. This had been donated by the Emperor of Constantinople, Baldwin II. Father Dionysius decided to donate to the Convent the valuable relic.