The relevance of the 1198 eruption of Solfatara in the Phlegraean Fields (Campi Flegrei) as revealed by medieval manuscripts and historical sources

The Phlegraean Fields (Campi Flegrei) caldera in Italy had one well-documented eruption during the historical period (1538). Another eruption at Solfatara in 1198 is reported by sixteenth and seventeenth-century scholars, and has been commonly regarded as uncertain. In this paper we first discuss the circumstantial evidence and report of this eruption, then discuss the relevance of drawings made in the thirteenth through the fifteenth century illustrating the Solfatara and the primary literary and historical sources describing the site. We infer that the eruption was at most a minor phreatic explosion and we explore the conditions that may have led to the occurrence of this event and the establishment of a small crater pool subsequently used as a thermal bath from the later Middle Ages onward.