Igilgili was initially a small Carthaginian colony and trading port. This name seems to combine with a suffix that might be either Semitic or Berber. After the Punic Wars, Igilgili was given to Rome's allies in North Africa. After the defeat of Jugurtha by Rome and its allies in 105BC, the city came under direct Roman rule. It was turned into a Roman colony under Augustus in 33 BC, giving its people Roman citizenship. Once the Romans occupied the whole of North Africa, the city of Igilgili was administratively attached to the Roman province of Mauretania Caesariensis and later to Mauretania Sitifensis. In those years, Igilgili grew to nearly 6,000 inhabitants and was very rich, with commerce to Italy and Iberia. Igilgili population and its surroundings became massively Christian in the fourth century, with the formalization of this religion under Emperor Constantine, although the first conversions date back to two centuries earlier. When emperor Valentinian I sent his magister militumTheodosius to attack Firmus, he landed in Igilgili in 374 AD; there Firmus tried to find a compromise with him, but Theodosius refused peace to Firmus, who had proclaimed himself emperor. With the support of the indigenous local African tribes, Firmus obliged Theodosius to a bloody and hopeless campaign in which Igilgili region was devastated for a couple of years. In the end, however, Firmus was betrayed by one of his supporters, and chose suicide over capture. The Roman city remained rich until the attack and partial destruction by the Vandals in 429 AD. Subsequently, the city was taken in 533 AD by the Byzantine and their Romano-African supporters from the Vandals. Catholicism and the Roman way of life were restored under the Byzantines, while the remaining Vandals took refuge in the surrounding mountains. At the time of arrival of the Umayyads and Islam in the region in the late seventh century, Byzantine officials with troops and some Roman Catholic and Latinized Berbers lived in the city of Igilgili. While nearby of the city the camps were populated by peasants Berber "Kutama", not fully Christians. Around 650 AD the first riders of Islam appeared. Queen Kahina was defeated in 698 AD by the Muslim troops of Hassan Ibn Numan and the city of Igilgili was renamed "Jijel". It was incorporated into the Umayyad empire. The population of the region, which was then mainly Christian, converted forcibly to Islam, and by the end of the eighth century it had already become overwhelmingly Muslim. The Arabic language there diffused slowly and gradually, replacing Latin in Jijel city only in the early eighth century.
