The Goddess Sul, or Sulis, was worshipped locally at Bath in Somerset, England, and was the deity associated specifically with the natural hot springs at Bath. She was called Sulis Minerva by the Romans occupying Britain during ancient times, a combination of the local name and that of the Roman goddess Minerva, who was the main goddess of the temple spa. The name Sulis may have originated from the Old Irish word “suil”, which means “eye” or “gap” and may describe the opening of the hot springs at Bath. Sulis became a Roman-Irish deity, that later evolved into a Celtic mythological figure.
Like most religions, Celtic mythology was influenced by other systems of mythology from Europe as well; there was a particular division of Celtic traditional beliefs that revolved around Greek or roman deities. The Celts gradually infused these gods and goddesses with their own religious figures, and adapted them into their every day religious faith and lives. Later, these part Roman, part Celtic deities lost their distinction; it became less significant as to which culture the originating influence derived from, and so the old multicultural deity became a god or goddess of the specific culture that had adapted it. Compare this to the theory that the Egyptian creature Apep was once the cheif god of a much older religion, that gradually became demonized according to the beliefs of the ancient Egyptians.
It is also likely that the word derived from a similar-sounding one meaning “good, flooding one.” This makes sense considering she was associated with the healing qualities of the spring. Sulis is described as being a life-giving, nurturing goddess, but also one who will deliver curses on the behalf of her loyal worshippers. When paired with the Roman goddess Minerva, she also takes on the qualities of wisdom and decision-making.