How a massive volcano helped to convert Iceland's pagans to Christianity

The eruption of the Eldgja volcano in Iceland in 939 may have influenced the country's conversion to Christianity.
The Icelandic poem Voluspa, written in 961 describes the volcano Eldgja and suggests about the advent of Christianity (Clive Oppenheimer)
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The volcano Eldgja

​A team of scientists, including Dr. Clive Oppenheimer, a volcanologist from the University on Cambridge in England, used information from ice core samples, as well as tree rings to pinpoint the previously unknown date of a massive volcanic eruption in Iceland. They determined that the volcano, known as Eldgja, erupted in 939. It was a slow motion, but massive eruption, and an estimated 20 cubic kilometres of lava flowed from the volcano, which makes it the largest lava flow in the history of Iceland. Approximately one-fifth of Iceland's population perished due to famine as crops failed and the air quality became poor due to the haze of sulphurous gases.

The Icelandic volcano Eldgja erupted in 939 along fissures like this one. (Clive Oppenheimer)

The poem Völuspá

Although there are no direct surviving accounts of the actual eruption, Eldgja does seem to be the inspiration for a poem written not long after. Iceland's most celebrated medieval poem, Völuspá, or "The prophecy of the seeress" was written in 961 and tells the story of both the creation and the end of the old world, and the rise of a new one. One stanza also provides a description of what the eruption may have been like. 

The sun turns black, earth sinks in the sea,
The hot stars down from heaven are whirled;
Fierce grows the steam and the life-feeding flame,
Till fire leaps high about heaven itself.   

Conversion to Christianity

The poem also describes the end of the pagan gods and the arrival of a new singular god as the eruption comes to an end. 

There comes on high, all power to hold,
A mighty lord, all lands he rules.
Rule he orders, and rights he fixes,
Laws he ordains that ever shall live.

Dr. Oppenheimer suggests that the poem was written from memories of the devastating eruption and subsequent rise of Christianity in Iceland. Iceland officially embraced Christianity only a few decades later.