Top-view of the Roman Baths in Bath.

The temple was constructed in 60–70 AD and the bathing complex was gradually built up over the next 300 years. During the Roman occupation of Britain, and possibly on the instructions of Emperor Claudius,] engineers drove oak piles into the mud to provide a stable foundation and surrounded the spring with an irregular stone chamber lined with lead. In the 2nd century, the spring was enclosed within a wooden barrel-vaulted building, which housed the calidarium (hot bath), tepidarium (warm bath), and frigidarium (cold bath).