How did Celtic settlers from Scotland and Ireland become part of Iceland’s early population?

Iceland’s early population was formed by a mix of settlers who arrived during the Viking Age, beginning around 874 CE. While the majority of these settlers were of Nordic stock from Norway, between 20 and 40 percent of the population originated from the British Isles, specifically Scotland and Ireland.12

These individuals of Celtic stock arrived in Iceland as part of the broader migration from Norse settlements established in those regions. Additionally, historical accounts suggest that Irish hermits had been visiting or living on the island in search of solitude prior to the arrival of the Nordic settlers, though these monks reportedly departed upon the arrival of the Norse people. Over the centuries, the early Nordic and Celtic groups merged completely, resulting in the homogeneous population found in modern Iceland.12