The Viking Age is the period A.D. 793–1066 in European history, especially Northern European and Scandinavian history, following the Germanic Iron Age. It is the period of history when Scandinavian Norsemen explored Europe by its seas and rivers for trade, raids and conquest. In this period, the Norsemen also settled in Norse Greenland, Newfoundland, and present-day Faroe Islands, Iceland, Normandy, Scotland, England, Ukraine, Ireland, Russia and Anatolia. Though Viking travellers and colonists were seen at many points in history as brutal raiders, many historical documents suggest that their invasion of other countries was retaliation in response to the encroachment upon tribal lands by Christian missionaries, and perhaps by the Saxon Wars prosecuted by Charlemagne and his kin to the south. or motivated by overpopulation, trade inequities, and the lack of viable farmland in their homeland. Information about the Viking Age is drawn largely from what was written about the Vikings by their enemies, and primary sources of archaeology, supplied with secondary sources like the Icelandic Sagas.