<P> During the reign of King Beorhtric of Wessex ( 786 -- 802 ) three ships of `` Northmen '' landed at Portland Bay in Dorset . The local reeve mistook the Vikings for merchants and directed them to the nearby royal estate , but the visitors killed him and his men . The earliest recorded planned Viking raid , on 6 January 793 , targeted the monastery on the island of Lindisfarne , off the north - east coast of Northumbria . According to the 12th - century Anglo - Norman chronicler Symeon of Durham , the raiders killed the resident monks or threw them into the sea to drown or carried them away as slaves -- along with some of the church treasures . In 875 , after enduring eight decades of repeated Viking raids , the monks fled Lindisfarne , carrying the relics of Saint Cuthbert with them . </P>
when did the vikings first sail and reach britain
786 -- 802