The story goes that a young and noble woman named Rosalia Sinibaldi spent her life as a hermit to escape a marriage wanted by her family. She died in the cave at the top of Monte Pellegrino where the sanctuary dedicated to her stands today. According to legend, Rosalia appeared to a sick woman in 1623 and later to a hunter, at the time when Palermo was hit by the plague of 1624. The Saint's apparitions were an expression of her wishes: she wanted her bones to be found in the grotto of Monte Pellegrino and brought to the city for a procession in her honour.
So, on 15 July 1624, her wish was fulfilled and the miracle took place: suddenly the plague that had been sweeping through the city leading to the decimation of the population disappeared and all the plague victims were cured. From that day on, Rosalia became the patron saint of the city and on 15 July each year u fistinu (the feast, in Sicilian) is celebrated with a long procession to pay homage to the saint.