Unraveling the Roman military presence at Optatiana/Sutor. The evidence of the tile-stamps

The systematic archaeological investigation of the Roman fort at Optatiana/Sutor, initiated in 2001, has provided substantial insights into the site’s military history. A total of 60 tile-stamps have been recovered, bearing the insignia of two distinct military units: Numerus Maurorum Optatianensium (58 items) and Cohors I Brittonum (2 items). Notably, 96.6% of the stamps are inscribed with the NMO abbreviation, indicating the presence of Moorish troops during the fort’s stone construction phase at Optatiana/Sutor. Although specific details regarding this unit are sparse, several key historical records shed light on their origins. The unit is first documented in three military diplomas from Upper Moesia, dated AD 146, AD 152, and AD 158, where they are identified as vexilarii Africae et Mauretaniae cum Mauri gentiles. suggests their arrival before AD 145–146, likely in response to the military campaigns of Antoninus Pius in Mauretania Tingitana and Caesariensis. After AD 160, these forces underwent reorganization into smaller units known as numeri, likely reflecting strategic adjustments within the Dacian army during the reign of Marcus Aurelius. As a result, the Numerus Maurorum Optatianensium likely arrived at Optatiana subsequent to this reorganization and played a significant role in the construction of the stone fort and adjacent civilian structures. Prior to the construction of the stone fort, an earlier turf and timber fort occupied the site, with dimensions roughly equivalent to the later structure, but the identity of the auxiliary unit responsible for its construction or garrisoning remains unknown. Similarly, a smaller earthen fort, discovered at the southwestern corner of the larger forts, is associated with the earliest phase of Roman occupation in Dacia, though its specific origins and military association also remain undetermined.