Urgo or Gorgòn (Γοργόν in Ancient Greek), believed to be Gorgona, receives brief mention in Pliny, who only states that it is near Pianosa and Capraia. Pomponius Mela had mentioned the name earlier (43 BC) but only as an item in a list of the islands in the vicinity.
Rutilius Claudius Namatianus in describing his voyage of 416 AD in the region says that "Gorgon" rises up in the middle of the sea between the Pisan and Cyrniacan (Corsican) shores. He had already stated that there were monachoi, "monks", on Capraia and now relates the story of an aristocratic youth who had given up wealth, status and the opportunity for marriage to retire to Gorgon in "superstitious exile", implying that monasteries of sorts were already on the two islands.
Tradition holds that monks from Gorgona rescued the relics of Saint Julia of Corsica before they were carried to the mainland in the 8th century. Finally, in 1425, the Saint Julia relics were carried to "Chartreuse of Calci", near to Pisa.
The monastery was abandoned after its destruction by the Saracens. In the 11th century the Republic of Pisa cleared the Tyrrhenian Sea of Muslims and proceeded against their strongholds in Africa. In 1051, just prior to the Pisan occupation of Corsica, the monastery was reconstituted, still Benedictine, and was declared under papal protection. Subsequently gifts of land were made by aristocrats in Tuscany (where Pisa is located) and northern Corsica. The monastery began to keep land records from Corsica, the first known from there.
Letter 130 of Catherine of Siena, a Dominican nun, to Ippolito degli Ubaldini of Florence encourages him to enter and contribute to the monastery of Gorgona. The letter in stating that the monastery needed to be refurbished to conform to the "rule of the Carthusian Order" implies that it was recently converted to that order. It must have been written after her vision of 1375