This picture, miniature 76 of the early 14th-century Manesse Codex, shows an apparently circular, single-poled tent with a narrow valence strip painted with dagged-looking decorations. Not much detail is visible, but one distinctive feature of the picture is that it shows hooks or cords, hanging from the bottom of (or behind) the valence strip, holding the doorway open.
I don't remember who pointed me to this one; sorry!