Andy Ross of Yell recently posted a reference to woollen sails which the Vikings used. (How does he manage to keep up with so much information?) The article is fairly long, but the preface will give you an idea of the research and conclusions. I see that Carol Christiansen of the Shetland Museum was one of the contributors. http://www.reikfelag.ca/files/Viking_woolen_sails.pdf
I also learned from both Andy's site and from Hazel Tindall about a TV presentation on BBC Four, titled "Handmade in Britain - Fabric of Britain: Knitting's Golden Age". I tried to watch it but was unable to make a connection from Canada. However, there was a fairly detailed description of the program which sounded very interesting. I see it is the first of a series. http://www.vam.ac.uk/content/articles/h/handmade-in-britain-really-ripping-yarns-knitting/
From Norway, there is a well-patched tunic on display in the Museum of Cultural History in Oslo. (I learned about this in a newsletter from the Smithsonian Magazine.) The tunic was found due to the melting of a glacier and is thought to have been worn 1700 years ago. http://blogs.smithsonianmag.com/smartnews/2013/09/melting-glaciers-are-liberting-ancient-clothes-like-this-1700-year-old-sweater/?