The stone structure is built round a natural hot spring and on a lintel there is an inscription thought to be the Hebrew word "zochalim", "flowing". This led to the theory that this was a mikveh or Jewish ritual bath. The interpretation of the inscription was challenged in 2002 and the alternative theory proposed that the bath is too deep for a mikvah and may have been used to cleanse bodies before burial in the nearby Jewish cemetery at Brandon Hill which was established after 1177. A Jewish community was known to exist in Bristol from at least 1154 until the wholesale banishment of the Jewish community from England in 1290.