 It fed a bathing complex on its south side within a barrel-vaulted building.The complex was gradually built up over the next 300 years.All the stonework above the level of the baths is from more recent periods 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.