History of the territorial distribution of the Frisian language:
  territorial distribution in 700 - 1100
  territorial distribution in 1100 - 1300
  territorial distribution in 1300 - 1600
  territorial distribution in 1600 - 1900
  territorial distribution in 1900 - nowadays
  nowadays territorial distribution
This vector image includes elements that have been taken or adapted from this file:
Dmitry Lavrinenko