This study examines landscape change in the Province of Jämtland during c. 1000–1750 AD. Settlement and arable cultivation are two of the most important sources in this study. They are therefore treated in depth, particularly farmsteads that were deserted during the late medieval agrarian crisis, so-called ödesbölen, and their fossil field-traces. The dissertation contains four major investigations. In the first investigation 610 possible ödesbölen were identified. The desertion was estimated at 50 per cent. The second investigation had its focus on the geographic location, and the conclusion was that the ödesbölen may have been deserted when the climate turned colder in the 14th century. The third investigation concerned medieval agriculture. Using historical maps and detailed mapping of fossil field traces it was established that the annually cultivated acreage decreased from the High Middle Ages until early modern times. This probably means that the agrarian crisis caused a change in the agrarian regime, from predominant arable farming to predominant stock-raising. The fourth investigation was whether the ownership or the use of the ödesbölen created obstacles to recolonization when the crisis subsided. This turned out not to be so in the case of ownership, but may have been so with regard to communal forest grazing. According to historical maps the ödesbölen in Jämtland were finally recolonized about 200 years later than for example in southern Sweden. The reasons probably were wars and a worse climate. The dissertation is capped off with both a model and a description of landscape change in Jämtland. Characteristic for the development of the landscape has been fluctuations in settlement. The ödesbölen are part of a pattern in which they are colonized, deserted, recolonized and again deserted in a cyclical course of events. The openness of the landscape is not part of this course of events.