Saxo Grammaticus,
The Danish History — Preface
“ In this island there is likewise a mountain, whose floods of incessant fire make it look like a glowing rock, and which, by belching out flames, keeps its crest in an everlasting blaze. This thing awakens our wonder as much as those aforesaid; namely, when a land lying close to the extreme of cold can have such abundance of matter to keep up the heat, as to furnish eternal fires with unseen fuel, and supply an endless provocative to feed the burning. ”
