Oea

The Phoenicians were probably attracted to the site by its natural harbour, flanked on the western shore by the small, easily defensible peninsula, on which they established their colony.

[citation needed] By the later half of the 2nd century BC, Oea was conquered by the Romans, who included it in their province of Africa, and gave it the name of Regio Syrtica.

Around the beginning of the 3rd century AD, it became known as the Regio Tripolitana, meaning "region of the three cities" (namely Oea (modern Tripoli of Libya), Sabratha and Leptis Magna).

The principal surviving monument (of Oea) is an elaborately ornamental quadrifrons archway dedicated to M. Aurelius and L. Verus in A.D. 163, the central stone dome of which was carried on flat slabs laid across the angles and was concealed externally within the masonry of an attic, now destroyed.

The city prospered mainly because Rome stopped bandits from plundering the countryside, but also because the Roman Empire – under Trajan and Septimius Severus – curbed unrest among local tribal groups by creating the Limes Tripolitanus and setting up towns such as Gaerisa, forts such as Garbia, and centenaria farms along the southern edge of the Oea territory.

At the Council of Carthage (255), which Cyprian called to discuss baptism administered by heretics, Natalis of Oea spoke in his own name and on behalf of the bishops of Sabratha and Leptis Magna.

[13] The diocese was mentioned in an early 8th-century Notitia Episcopatuum of Alexandria and in that of Byzantine Emperor Leo VI the Wise at the end of the 9th century,[14] No longer a residential bishopric, Oea is today listed by the Catholic Church as a titular see.

[15] There is evidence that the Tripolitania region was in relative economic decline during the 5th and 6th centuries, in part due to the political unrest spreading across the Mediterranean world in the wake of the collapse of the Western Roman Empire, as well as pressure from the invading Vandals.