The baths have been modified on several occasions, including the 12th century, when John of Tours built a curative bath over the King's Spring reservoir, and the 16th century, when the city corporation built a new bath (Queen's Bath) to the south of the spring. The court physician Théodore de Mayerne bathed Anne of Denmark in the King's Bath on 19 May 1613. She returned in August 1615. Anne of Denmark was surprised by a flame caused by natural gas in King's Bath, and therafter used the New Bath or Queen's Bath where a column with a crown and the inscription "Anna Regnum Sacrum" was added in her honour.