Main article: Christianity in Albania

Christianity came to Epirus nova, then part of the Roman province of Macedonia.[31] Since the 3rd and 4th century AD, Christianity had become the established religion in Byzantium, supplanting pagan polytheism and eclipsing for the most part the humanistic world outlook and institutions inherited from the Greek and Roman civilizations. The Durrës Amphitheatre (Albanian: Amfiteatri i Durrësit) is a historic monument from the time period located in Durrës, Albania, that was used to preach Christianity to civilians during that time.

When the Roman empire was divided into eastern and western halves in AD 395, Illyria east of the Drinus River (Drina between Bosnia and Serbia), including the lands form Albania, were administered by the Eastern Empire but were ecclesiastically dependent on Rome. Though the country was in the fold of Byzantium, Christians in the region remained under the jurisdiction of the Pope until 732. In that year the iconoclast Byzantine emperor Leo III, angered by archbishops of the region because they had supported Rome in the Iconoclastic Controversy, detached the church of the province from the Roman pope and placed it under the patriarch of Constantinople.

When the Christian church split in 1054 between Eastern Orthodoxy and Catholicism, the region of southern Albania retained its ties to Constantinople, while the north reverted to the jurisdiction of Rome. This split marked the first significant religious fragmentation of the country. After the formation of the Slav principality of Dioclia (modern Montenegro), the metropolitan see of Bar was created in 1089, and dioceses in northern Albania (Shkodër, Ulcinj) became its suffragans. Starting in 1019, Albanian dioceses of the Byzantine rite were suffragans of the independent Archdiocese of Ohrid until Dyrrachion and Nicopolis, were re-established as metropolitan sees. Thereafter, only the dioceses in inner Albania (Elbasan, Krujë) remained attached to Ohrid. In the 13th century during the Venetian occupation, the Latin Archdiocese of Durrës was founded.