The three metals used most in the construction of the Baths were iron, lead, and bronze, which not surprisingly were also the three most common non-precious metals used in antiquity. Despite their ubiquity, information on the production of these materials and the organization of their supply to Rome is limited, and identifying their precise sources is impossible.
The Date of Construction
The construction of the Baths of Caracalla is usually assigned broadly to the reign of Caracalla, and often to 212-216. This commencement date of 212 is taken from the brick stamps, most of which can be assigned to the sole reign of Caracalla. We can probably be more specific since the bricks were stamped after being formed but before they had dried, and brick-making was restricted to the drier months of the year, the earliest that bricks bearing Caracalla’s name alone could have been put in place would have been about May 212. Given that stamps of this kind have been found in substructures and drains, and that before these were begun the Baths had to be designed, the land acquired, the site terraced, the building surveyed and the foundations dug and filled, it is possible to argue that the project was conceived in 211, if not before. Jerome gives the date of construction as 216, and this is usually interpreted as the date of dedication.
The Date of Construction
