Acorns

Prince Bladud lived around 800 BC and was the son of Lud Hudibras, King of the Britons. After contracting leprosy on his travels abroad, he was banished from the tribe and found work as a swineherd in the Avon Valley. Unfortunately his pigs became infected too. In Swainswick the pigs began to wallow in hot mud. To entice them out, Bladud climbed an oak tree, collected some acorns and made a trail out of the water. As the pigs climbed out he scraped the mud from their skin to find that it was cleansed and cured. He jumped in and emerged to find his skin clear and his leprosy, healed. The Prince returned to the tribe in triumph. When Bladud became King he established a settlement in Bath and the city grew around the temple he built by the hot springs.
The Circus' parapet is adorned with stone acorn finials in reference to this story.