Montecristo, also Monte Cristo (ˌmɒntiˈkrɪstoʊ, ˌmonteˈkristo) and formerly Oglasa (Ōglássa), is an island in the Tyrrhenian Sea and part of the Tuscan Archipelago. Administratively it belongs to the municipality of Portoferraio in the province of Livorno, Italy. The island has an area of , is approximately wide at its widest point, and is long; the coasts are steep, and extend for . The island is a state nature reserve and forms part of the Tuscan Archipelago National Park. Much of the island's fame is derived from the fact that it provides the title of 1844 novel The Count of Monte Cristo, by Alexandre Dumas, and is one of the novel's settings. The history of the island begins with the Iron Age. The Etruscans exploited the forests of oak needed to fuel the bloomeries of the mainland where the iron ore of Elba's mines was melted. The Greeks gave Montecristo its oldest known name, Oglasa or Ocrasia, after the yellowish colour of the rocks. The Romans, however, knew it under the name Mons Jovis ("Mount Jupiter"), and erected an altar to Iuppiter Optimus Maximus on the highest mountain, of which some traces remain. During the imperial age, the Romans opened some quarries to extract granite, perhaps used in the construction of villas on the islands of Giglio, Elba, and Giannutri. Around the middle of the fifth century AD, the caves of the island became home to several hermits escaping from the Vandals of Genseric, the most important of whom was St. Mamilian. They christened the island Mons Christi ("Mountain of Christ"), from which the modern name is derived. At the beginning of the seventh century, Pope Gregory the Great submitted them to the monastic rule of the Benedictines. In this period, the Monastery of St. Mamilian was founded; as a result of donations to the Church, its wealth became legendary, and a chapel was built in the St. Mamiliano Cave where the saint had lived in the fifth century. In 1216, the monks joined the order of the Camaldolese.