The Prologue gives an overview of historical knowledge about Norse settlements in Greenland. The purpose is to outline the factual backdrop against which we must evaluate the tales and legends about the vanished settlers. A short summary of the history of the settlements preserved in Icelandic sagas is provided. The sagas tell us south-eastern Greenland was settled as a westward relocation of Icelandic farmers, a migration first promoted by Erik the Red. It is of particular interest in this section of the book to unravel why the first colonisation of Greenland came to an end in the fifteenth century. Thus, the major current theories for the demise of the settlements are outlined and the scientific debates are explained and appraised. Although the mystery of when and why the Norse Greenlanders abandoned Greenland has never been conclusively resolved, a number of factors appear to have been important triggers, such as change towards a colder climate. Yet there is today a growing consensus in the scientific community that the Greenlanders’ inability to sell their walrus ivory led to the settlements becoming unsustainable.