Slavs
The Slavic autonym is reconstructed in Proto-Slavic as *Slovenin', plural *Slovene. The oldest documents written in Old Church Slavonic and dating from the 9th century attest Slovene Slovene to describe the Slavs. Other early Slavic attestations include Old East Slavic Slovene Slovene for "an East Slavic group near Novgorod." However, the earliest written references to the Slavs under this name are in other languages. In the 6th century AD Procopius, writing in Byzantine Greek, refers to the Sklaboi Sklaboi, Sklabenoi Sklabenoi, Sklauenoi Sklauenoi, Sthlabenoi Sthlabenoi, or Sklabinoi Sklabinoi, while his contemporary Jordanes refers to the Sclaveni in Latin.
Who wrote about the Slavs in Byzantine Greek in the 6th century?
Procopius
In the 6th century AD Procopius, writing in Byzantine Greek, refers to the Sklaboi Sklaboi, Sklabenoi Sklabenoi, Sklauenoi Sklauenoi, Sthlabenoi Sthlabenoi, or Sklabinoi Sklabinoi, while his contemporary Jordanes refers to the Sclaveni in Latin.
Slavs