2. Roman Mints
In the majority of instances there is very little known about the location of the Roman mints, although approximate locations are known in some cases. As far as Rome itself is concerned, two sites are known. In Republican times a mint was situated next to the Temple of Juno Moneta on the Capitoline Hill, conveniently close to the city treasury in the Temple of Saturn. At some time between the reign of Vespasian and the early second century a new location was found for the mint on the Caelian Hill near the modern church of S. Clemente.
Control of the mints changed over the years. In the latter years of the Republic, a group of mint magistrates reporting to the senate were responsible for overseeing coin production. Mint magistrates were usually three in number being elected annually. By the time of Trajan, mint magistrates were replaced by the procurator monetae and from the reign of Diocletian each mint had its own procurator.
The mint director (procurator monetae) was responsible to the central imperial finance office and he was given instructions as to what metals had to be coined, at what weight the coins had to be produced, when to coin and which issues (or types) were to be produced. "Type of coin" refers to the mark or design that separated coinage from bullion. This mark or design acted as a stamp of authority that guaranteed the value of the coin. Two inscriptions from the Electronic Archive of Greek and Latin Epigraphy (EAGLE) make reference to procuratores monetae who at some stage of their careers came from, or lived at Ostia - EDR072778 and EDR072626.
Below the procurator were several heads of technical and production staff (praepositi and officinatores). CIL XIV, 1878 (EDR143488) refers to one such praepositus of the OFFICINA PRIMA who died at the age of 34. Officinatores were below praepositi, but senior to the manual workers: the signatores, scalptores, suppostores and malleatores. (die-letterers, die-cutters, those who positioned the flans and those who struck the coins respectively).
Mints usually consisted of a number of officinae or workshops - the highest number known is fifteen at the Antioch mint under Constantius II. Officinae are easier to identify with the advent of mintmarks in the middle of the 3rd century, but their mode of operation was extremely variable. Sometimes an officina struck specimens of all coins, but they may have also only struck coins for individual members of the imperial family. It has been suggested that certain officinae at Ostia were used for producing special issues in small numbers. In some cases, an officina was restricted to the production of a single reverse type.
The assumption is made that officinae were all under one roof and it could well be that officina marks refer to different shifts within the mint.