In the 2nd century, the city possessed monuments and dedications to the emperor Verus and to the emperor Marcus Aurelius. Around 384, Donatist schism caused a conflict in the region. Emperor Constant I sent emissaries to reconcile the two religious parties, but the dissent lead to open revolt. The massacre of Bagai resulted. The Council of Bagaï took place on 24 April 394 to discuss the Donatist question. The city was a stronghold of Donatism and in 411, a Donatist bishop was sent from Bagai to the Council of Carthage. The city was the most important capital in the conflict between Donatists and Catholics during the Late Empire. In the election of Primianus of Carthage, the region burst into flames again. The Berbers destroy the city and ransack the library. In the 5th century, Baghai was invaded by the Vandals, driven afterwards by the Berbers. In 538, Gontharis, an officer of Byzantine general Salomon who reconquered the ancient Roman Africa settles his camp near the deserted city, but was defeated by the Berbers who regained control of the city, and strengthened it by surrounding it with an enclosure. It is the starting point of his second campaign in the Aures. In the Middle Ages, the Umayyads attacked the city, the Kahina rebelled against Hassan ibn Numan in 698. The Berber queen destroyed the city and left nothing to the Umayyads. Subsequently, the Fatimids took the city in 903. In 943, Abu Yazid takes the city, but after his death the city falls into the hands of the Zirids and then the Hammadids in 1015. The latter will attack the inhabitants of the city. Subsequently, the Hilalians destroyed the whole city. Al Idrissi mentions that there was a double wall in the city in his writings before it was destroyed.
Etymology
The city was called by AugustineVagaïa. Procope of Caesarea transcribed it Bagaè and the Arab historians wrote Baghaïa.
Bishopric
Bagai was the seat of an ancient Catholic bishopric in Numidia, and a center of Donatism. Bagai was the home of Donatus of Bagaifl 347 and Marculus of Bagai fl 347. Augustine wrote of many leading citizens of Bagai. In 340 Bagai was the site of a massacre by imperial legate Macarius which forever fractured the possibility of conciliation between Donatist and Catholic factions and made the schism increasingly violent. In 401, divisions were still so strong in Bagai that when the Donatist bishop Maximian of Bagai converted to Catholicism he was twice nearly murdered, such that Augustine once said of him "He has more scars than limbs". The Donatist Council of Bagai was held with 310 bishops in 394 AD. The Council of Bagai condemned Maximianist and supported Primian of Carthage as Primate of Africa. The diocese survives today as a titular see of the Roman Catholic Church.