The sagas was also mostly written down in the 11th century, long time after the event, based on the oral tradition. Although they put more pride into retelling

The sagas was also mostly written down in the 11th century, long time after the event, based on the oral tradition. Although they put more pride into retelling stories accuratly back then, it is not unlikely that the details had altered during that period. There are many other sides of the sagas that have proven inaccurate. For the sea level, this is areas that was covered by ice during the last ice age, and these areas have been rising since then. Some areas, like around the Botnian Sea, is still rising even today, so archaeological sites that was on the seashore will be there or slightly inland.