Saint Rosalia
Saint Rosalia is the patron saint of Palermo, Sicily, (Italy) and El Hatillo, Miranda (Venezuela).
According to legend Rosalia was born in 1130 of a Norman noble family that descended from Charlemagne. A very pious young lady, she retired to live as a hermit in a cave on Mount Pellegrino, where she died in 1166. Nobody knew anything about her demise.
In 1624 a horrible plague haunted Palermo, and during this hardship St. Rosalia appeared first to a sick woman, then to a hunter to whom she indicated where her remains were to be found. She ordered him to bring her bones to Palermo and have them carried in procession through the city.
The hunter climbed the mountain and found her bones in the cave as described. He did what she had asked in the apparition, and after the procession the plague ceased. After this St. Rosalia would be venerated as the patron saint of Palermo, and a sanctuary was built in the cave where her remains were discovered.
The celebration, called the festino, is still held each year on July 15. It is still a major social and religious event in Palermo. Also on September 4 there is an event related to the festino and St. Rosalia; a tradition of walking on bare feet from down (Palermo) to up Mount Pellegrino. In Italian American communities in the United States, the July feast is generally dedicated to Our Lady of Mount Carmel while the August feast brings large numbers of visitors annually to the Bensonhurst section of Brooklyn in New York City.
In Biology
Saint Rosalia was proposed as the patron saint of evolutionary studies in a classic paper by G.E. Hutchinson (available here). This was due to a visit he paid to a pool of water downstream from the cave where St. Rosalia's remains were found, where he developed ideas based on observations of water boatman. The article, and its reference to St. Rosalia has lived on through the literature, often in the title of papers concerning biodiversity.