The Vinland map

The Vinland Map was discovered in 1957, bound up with a manuscript of undisputed antiquity, the Historia Tartorum. The map supposedly is a 15th century copy of a 13th century world map, showing the known parts of Europe, Asia and Africa, as well as an unknown land across the Atlantic Ocean labelled Vinland. The map also mentions that Vinland was visited in the 11th century.
This corresponds well with a tradition in Viking folklore that Norsemen, using Iceland and Greenland as stepping stones, had a more or less regular contact with North America. According to some Icelandic sagas, North America was sighted in about 986 by Bjarni Herjolfsson, who was blown off course on a trip from Iceland to Greenland. His stories lured Leif Eiriksson on an expedition in the year 1000, on which he named (north to south):
Helluland (“Flatstone Land” – possibly present-day Baffin Island)
Markland (‘Wood Land’ – possibly Labrador) and
Vinland (‘Grapevine Land’ or ‘Pasture Land’ – possibly Newfoundland)