Historically, an administrative division of Norway in Sønnenfjells and Nordenfjells has been used from the Middle Ages until around 1800.
The border between the two regions was a range from Åna-Sira or Lindesnes, northwards along Langfjella and Dovrefjell.
Erik Pontoppidan was one of the first to use the notion of vestenfields (west of the mountains) as distinct part of Nordenfjells.
Christopher Hansteen travelled across Hardangervidda in 1821 and observed that his compassed apparently had a 90° deviation: People in Eastern Norway said they traveled "north" to Hardanger and people from the west were known as "nordmenn".
[2][3] Norge (Norway) and nordmenn in the Middle Ages were names for the coastal areas from Agder to Hålogaland, and the people there.