In Europe, it took the form of ‘Christianizing’ missionaries, many of them Irish, who wandered alone or in small groups into the forests of eastern and northern Europe. As historians E.O.G. Turville-Petre and Edgar Charles Polomé write,
The Germanic peoples were converted to Christianity in different periods: many of the Goths in the 4th century, the English in the 6th and 7th centuries, the Saxons, under force of Frankish arms, in the late 8th century, and the Danes, under German pressure, in the course of the 10th century.
The history of Iceland is in many ways different than other parts of the world. It was essentially uninhabited until sometime in the eighth century. Around 750 A.D., give or take a few decades, the first permanent settlements on Iceland were founded.
These original residents of Iceland were Christians from Ireland. In later centuries, additional Irish arrived, as well as settlers from Scandinavia, some of whom were Christians, and some of whom were not. Turville-Petre and Polomé note that
Icelanders were, in many ways, the most international of northern Scandinavians. Among those who settled in Iceland in the late 9th century were men and women partly of Norse stock from Christian Ireland. Some of these were Christians; some were mixed in their beliefs, worshiping Christ and Thor at once.
Iceland is therefore distinctly different from other territories in that it did not require ‘Christianizing’ because its initial founders were Irish monks.
Despite the occasional bloody feud, the Icelanders of varying faiths enjoyed a mostly peaceful existence. Perhaps this was caused by, or perhaps this caused, Iceland’s famed early development of freely-elected representatives.
Long before other nations, around 930 A.D., the Icelanders formed their Althing, a sort of parliament or congress, and became a republic with freely-elected representatives.
With this metamorphosis toward democracy, faith in Norse mythology declined. Again, cause and effect are not easily discerned: did democracy cause a decline in paganism, or did a decline in paganism cause democracy?
In any case, Turville-Petre and Polomé report that
Lack of faith in the heathen gods seems to have grown during the 10th century.
When the Althing eventually embraced Christianity as the nation’s religion, it did so with the explicit proviso that those who wished to remain with Norse polytheism be allowed to do so, and should not be harassed for doing so.
But within a few decades, Norse mythology had ceased to be an operative belief system for all but a few Icelanders. Traces of the Norse characters and narratives remained in folk art, but not as objects of dynamic faith.
One consequence of Iceland’s unusual developmental path is that, in terms of gaining legal, social, political, and economic equality, Icelandic women were ahead of their peers in other nations.