In the late tenth century, the pagans and Christians of Iceland were gathering at Þingvellir (pronounced Thingvellir), a region in the Western part of the country surrounded by lava fields, to debate whether the entire nation ought to convert to Christianity. Then a volcano erupted. According to legend, a pagan stood and declared that the gods were angry and Iceland should reject Christianity. But then the prominent chieftain Snorri Goði (pronounced gothi) stood and asked the room, “Then what were the gods arguing about when the lava we are now standing on burned?”
This account, passed on by Scandinavian literature expert Sian Grønlie of Oxford University, is typical of Iceland in that era: pagans dealing with the rise of Christianity as the latter’s all-encompassing explanation for the world replaced local rites and customs. All the while, the nation’s volcanoes were as active as ever, with each eruption described as a miracle or just another Tuesday depending on who you asked and whose worldview stood to benefit from an explanation.
“One thing that struck me working on volcanoes around the world is that pretty much anywhere you find volcanoes that have been active in living memory, you find cosmologies that are shaped around that activity,” says Clive Oppenheimer, a volcanologist at University of Cambridge. “It would be very strange if you didn’t fit a volcano and its activity somehow into your cosmology if you lived around one. It would be very strange if you pretended it wasn’t there or you didn’t wonder about its activity.”
Oppenheimer recently implicated one volcanic eruption in particular as a cause for Iceland’s official conversion to Christianity, or at least as a tool used to justify that conversion to the next generation.
The Eldgjá eruption of the 10th century is the largest volcanic eruption in Iceland’s known history. In March, Oppenheimer finally pinned down the exact year in which the eruption occurred—something past researchers had only been able to guesstimate.