I believe this was the shield of Wilhem Ritter Von Bamburg, who was a major idiot in the late Middle Ages. He kept falling into the river drunk on cheap wine, so the mayor made him lord of the Alpine towels.

Reminds me of something Vimes would have seen in Discworld when he was researching coats of arms.

They were a clean family, a rare, and notable trait in the Olden Days.