Calogerus was a 5th-century monk from Chalcedon who later lived as a hermit in Sicily. To avoid persecution for opposing Arianism, he fled Africa and eventually settled in the Sicilian region. He served as a missionary on the island of Lipari before retiring to a solitary life on Monte Kronio. Known as Calogerus the Hermit, he is recognized as a saint within both the Catholic and Orthodox traditions.