click on the pic below to enlarge.
This appears to be drawings from the period...possibly Durer or a student of his. These are clearly "studies", that is to say, not meant to be finished paintings, but rather detail elements that can be presented to a patron for approval. It looks like a broken up portfolio, and is hanging on the wall in Prague Castle. Knowing the European way of doing things, these are probable originals.
Items of particular note include the stunning sword knot shown third from the bottom on the right hand side. Its a fancy enough knot that the artist really got into the details of it. He shows the finished knot, and then details of how it must have been made.
(That the artist has an eye for detail can be seen by the studies of the forshortened heads of the horses second from the bottom, left hand column.)