An old Roman sketch in a museum in London. This was found among many things. It is a lighthouse. The Romans built many of these around the coast of Britain. There were a few at Dover - the Roman gateway into Ancient Britain.
By Hadrian's wall, archaeologists found a treasure trove of 'what seemed' like post cards. On each of these square papers, like the image, there were writings of various things.
It gave an insight to what life was like for the Roman communities that manned the the great wall. It is possible that this post card was among such finds, though most had writing concerning orders or messages about duties upon the wall.