Religion in Iceland has been predominantly Christianity since its adoption as the state religion by the Althing under the influence of Olaf Tryggvason, the king of Norway, in 999/1000 CE. Until then, in the 9th and 10th centuries, the prevailing religion among the early Icelanders — who were mostly Norwegian settlers fleeing Harald Fairhair's monarchical centralisation in 872–930, with some Swedes and Norse British settlers — was the northern Germanic religion, which persisted for centuries even after the official Christianisation of the state.