A series of Earth-shattering volcanic eruptions in Iceland during the Middle Ages may have spurred the people living there to turn away from their pagan gods and convert to Christianity, a new study finds. The discovery came about thanks to precise dating of the volcanic eruptions, which spewed lava about two generations before the Icelandic people changed religions. But why would volcanic eruptions turn people toward monotheism? The answer has to do with the "Voluspa," a prominent medieval poem that predicted a fiery eruption would help lead to the downfall of the pagan gods, the researchers said. Historians have long...