Mystery Leopard

A heraldic leopard in a mosaic outside the town archives. It's a mystery lost to time as to exactly why the town of Shrewsbury, in a region that has a noticeable absence of leopards, should have three of them on the town crest - I've just googled to try and find the reasonably concise version I read once some years ago and instead found several others, one of which offered an entirely different explanation, so a mystery it must remain.