A buff coat is a heavy leather coat or vest worn by itself or under armor in the 16th and 17th centuries. Infantry versions seem to have been largely sleeveless, while cavalry versions had sleeves. The 16th century coats ended about the waist, like doublets and vests at that time, 17th century buff coats ussually had "flaps" hanging down to just above the knee, similiar to jupons. All in all, I would say they are the successor to the arming doublet, aketon or gambeson of earlier periods. They were sometimes also worn alone as protection from the weather or swords as they were said to be tough enough to stop a sword cut, or with piece plate like an almain collar. They are very versatile for creating an "armor look" in that regard. I'm planning on ordering an almain collar from Allan at Merc Taylor to do a border reiver impression.
