Hadrumetum (ADRUMETUM, also ADRUMETUS), a titular see of Byzacena. Hadrumetum was a Phcenician colony earlier than Carthage, and was already an important town when the latter rose to greatness. Hannibal made use of it as a military base in his campaign against Scipio at the close of the Second Punic War. Under the Roman Empire it became very prosperous; Trajan gave it the rank of a colonia. At the end of the third century it became the capital of the newly-made province of Byzacena. After suffering greatly from the Vandal invasion, it was restored by Justinian, who called it Justinianopolis. It was again afflicted by the Arabs (to whom it is known as Susa) and restored by the Aglabites in the eleventh century. In the twelfth century the Normans of Sicily held it for a time; the French captured it in 1881.
Susa has today 25,000 inhabitants, of whom 1100 are French, and 5000 are other Europeans, mainly Italians and Maltese. It is a government center in the Province of Tunis. It has a few antiquities and some curious Christian catacombs. The native portion of the town has hardly altered. It has a museum, a garrison, an important harbor, and there are many oil wells in the neighborhood.
Between 255 and 551 we know of nine bishops of Hadrumetum, the last of whom was Primasius, whose works are to be found in P.L., LXVIII, 467.