Both of the above images are from the early part of the 15th century - the first is from between 1405-1410- and were a couple of my inspiration images for making a Houppelande gown.
I had to go to an SCA event that had a theme of late 14th/early 15th century. I've wanted to make a houppelande for a while so this was as good an excuse as any.
For the sleeves, I made a simple basic sleeve and then, rather than have the sides taper, I made them as big as I could at the wrist. I ended up having to add gores to the sleeve to make it even bigger.