The daughter of Sinibald, Lord of Roses and Quiquina, Saint Rosalia was a descendant of Emporer Charlemagne was born in the year 1130 in Palermo, Sicily. She was devoutly religious, and when she reached adulthood, two angels led her to cave to live alone as a hermit. Upon the cave wall she wrote:
"I, Rosalia, daughter of Sinibald, Lord of Roses, and Quisquina, have taken the resolution to live in this cave for the love of my Lord, Jesus Christ"
She spent the final years of her life in this cave on Mount Pellegrino, three miles from Palermo, in an effort to overcome the worldly desires in her life. From this spot, she could see her paternal home. She died alone in 1166 at the age of 35.
When the plague hit Palermo in 1624, Saint Rosalia appeared twice. In her first visit she appeared to a sick woman, and the second to a hunter. She directed the hunter to locate her cave and find her remains; once found they were to be paraded around the city three times. After the three trips around the city, the plague disappeared from the city and those suffering were then healed. This act solidified her as the Patron Saint of Palermo.
Each year on July 14th, the city of Palermo holds the Festino di Santa Rosalia - a two day festival and major social and religious event in the city. On September 4th of each year, locals and tourists walk barefoot from Palermo to Mount Pellegrino to honor her. The Bensonhurt section of Brooklyn (NYC) hosts large crowds during the September feast in her name each year. In biology, Saint Rosalia is considered the patron saint of evolutionary studies due to a visit G.E. Hutchinson made to a pool of water downstream from her cave.
Pope Pius XI made her feast day a holy day of obligation in 1927.