I have been out for the weekend and visited a friend who is working in a museum and is an expert for bows, among others. During the last weeks he has recreated two different types of crossbows. You can see them here:
First one was found in Denmark in Boringholm - there was an old castle in former times. The Corss bow is from the 12.Century
The second crossbow is from the 11.Century and was found in France I found only this link. There is a short description at the end in three languages.
http://books.google.de/books?id=lQ6AhnGOj2MC&pg=PA32&lpg=PA32&dq=Cl.Fouilles+de+Colleti%C3%A8re&source=bl&ots=gdzUnOyMgk&sig=hokoWHxDF4vcezjPyX-drqYxFsY&hl=de&ei=Xi_ATpWMDdHwsga3qvGUAw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CB0Q6AEwAA#v=onepage&q=Cl.Fouilles%20de%20Colleti%C3%A8re&f=false
I think both are very beautifully handcrafted and I want to show the pictures here in the forum.