Merging technologies in North African ancient architecture: opus quadratum and opus africanum from the Phoenicians to the Romans

Using the examples of opus quadratum and opus africanum, this study discusses the interconnection between traditions and techniques of construction which typifies the architecture of North Africa between the second century BC and the early Imperial period. To understand how the Hellenistic and Roman traditions are grafted onto their predecessors, the analysis begins with the Phoenician period. New hypotheses are also proposed about the two techniques, based on typology and the construction process. The analysis does not confirm earlier hypotheses about their Phoenician origin. Opus quadratum was used at Carthage in the fifth century BC and spread from there during the second century BC, as exemplified by the mausoleum at Thugga. Opus africanum appears at Carthage in the seventh century BC, but the more complex versions are found both at Bulla Regia and at Carthage from the second century BC. The reasons for using this technique are clarified, starting from its diffusion in Morocco and by analysis of the Capitolium at Sala.