The Romans built the baths as part of a spa , in the year 43 BC , but they called it Aquae Sulis , which means `` The waters of Sulis '' ( Sulis was a Roman goddess ) Because of the baths and the architecture of the city ( the style of the buildings ) , Bath was named a World Heritage Site in 1987 .
Archaeological evidence shows that the site of the Roman Baths ' main spring was treated as a shrine by the Iron Age Britons , and was dedicated to the goddess Sulis , whom the Romans identified with Minerva ; however , the name Sulis continued to be used after the Roman invasion , leading to the town 's Roman name of Aquae Sulis ( literally , `` the waters of Sulis '' ) .