The German historian Gottfried Schramm (1994) suggests an origin of the Albanians in the Bessoi, a non-Romanized Thracian tribe that lived in the mountain regions of Dacia Mediterranea and Dardania, located in southern Serbia, Kosovo and north-western North Macedonia, and was Christianized as early as during the 4th century. Schramm argues that such an early Christianization would explain the otherwise surprising virtual absence of any traces of a pre-Christian pagan religion among the Albanians as they appear in history during the Late Middle Ages. According to this theory, the Bessoi were deported "en masse" by the Byzantines at the beginning of the 9th century to central Albania for the purpose of fighting against the Bulgarians. In their new homeland, the ancestors of the Albanians took the geographic name "Arbanon" as their ethnic name and proceeded to assimilate local populations of Slavs and Romans.