I finished reading Toini-Inkeri Kaukonen's 100-page study
Alusvaipat eli villalakanat or "On the history of Finnish woolen bed sheets" from 1961. Still during the 1950s some two percent of the rural population slept on the floor of their houses (which was customary up to the mid-19th century) and used woolen bed sheets on top of layer of straws. The sheets were not called blankets, although they basically were one and the same thing. The benefit of making twill woolen ones instead of linen ones was that the first ones lasted up to twenty years and had to washed only once during a year, after or during the winter.
It is not mentioned on the article but I suspect that the bed sheets were also carried by hunters and fishermen and used on top of a layer of spruce needles if they did not have a reindeer or sheep hide with them. The oldest reference we have on these is the
1483 inventory (in Swedish) from the castle of Viipuri.
Finally two photographs of the designs used in the bed sheets.
East Karelia
East Karelia