Leptis Magna is a Roman archaeological site on the Mediterranean coast of Libya, a hundred kilometres east of Tripoli at the mouth of the Wadi Lebda. The pre-Roman settlement was a Phoenician-Punic colony of the seventh or sixth century BCE founded on a pre-existing Berber-Libyan coastal site; the Berber-Libyan substrate is preserved in the modern Arabic toponym Lebda, which has continuous attestation alongside the Latin Leptis from the antique period to the present.
The city was the largest urban centre of Roman Tripolitania and one of the principal cities of Roman Africa Proconsularis. Under Septimius Severus, who was born at Leptis Magna in 145 CE and who became Roman emperor in 193, the city was substantially expanded and monumentalised: the Severan forum, the Severan basilica, the new harbour, the colonnaded street, and the Arch of Septimius Severus all date from his reign and define the surviving archaeological record. Septimius Severus's Berber-Punic origins — his family was Punic-speaking and culturally embedded in the local Tripolitanian sphere — make him conventionally treated as the only Roman emperor of explicitly north-African background.
The decline of the city is conventionally dated to the late fourth and fifth centuries, with the cumulative pressures of fiscal contraction, the Vandal sack of 455, the Berber raids of the late fifth century, and the silting of the Wadi Lebda that closed the harbour. The Byzantine reconquest of the sixth century did not restore Leptis to its earlier importance; the Arab conquest of the late seventh century definitively closed the Roman city.
Leptis Magna was inscribed by UNESCO as a World Heritage Site in 1982 and is among the most extensive surviving Roman urban sites in the world. The 2011 Libyan war and the subsequent post-Gaddafi instability have produced significant management and conservation challenges; sustained UNESCO and international heritage attention since 2015 has partially stabilised the site.