Unregistered

I have been looking for this painting for a few years now, and need help! I found it in the pages of one of my high school textbooks and I haven't seen it since.
It is a painting/drawing of a few things:
The main focus of the picture is a couple on a horse, being a knight and a maiden who is seated with him. If she is behind or in front of him I cannot recall. She is in a dress and him in armor I believe. There are hunting dogs around the horse's feet and they are brown greyhounds it looked like. The horse has it's neck tucked into it's chest a ways and is either white or gray. The couple on horse take up the entire scene, and I cannot remember the
background.
If you know the title or artist, please do email me at paintball_pegasus@yahoo.com.
Thanks!