Complex sentence: The Viking Runestones are runestones that mention Scandinavians who participated in Viking expeditions in western Europe, and stones that mention men who were Viking warriors and/or died while travelling in the West.
Split into simpler sentences: The Viking Runestones are runestones that mention Scandinavians who participated in Viking expeditions. This article treats the runestone that refer to people who took part in voyages abroad, in western Europe, and stones that mention men who were Viking warriors and/or died while travelling in the West.