This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Christianity is established across Scandinavia through three distinct national processes crowded into little more than a single generation around the year 1000. In Denmark, around 965 CE, King Harald Bluetooth raised the great rune stone at Jelling declaring that he had made the Danes Christian, a royal political statement rather than a settled description of a completed popular conversion already finished on the ground.
In Norway, Olaf Tryggvason, king from 995 to 1000, and his successor Olaf Haraldsson pursued Christianisation through direct royal pressure, including outright force, a policy that divided the country and at times threatened civil war between rival religions rather than achieving any peaceful consensus.
Iceland took a different path entirely. Rather than royal decree or force, the Althing, the island's own governing assembly, voted by peaceful mediation in the year 999 or 1000 to require baptism of all Icelanders, a rare case anywhere in this history of a whole people's religious status being settled by parliamentary compromise rather than conquest or royal fiat. What this changed for Christianity's spread was the faith's establishment across the whole Scandinavian world within a single generation, achieved by three genuinely different routes, royal statement, royal force and popular vote, rather than one common method.