The linguistic affinities of early Nubian cultures are uncertain. Some research has suggested that the early inhabitants of the Nubia region, during the C-Group and Kerma cultures were speakers of languages belonging to the Berber and Cushitic branches respectively, of the Afroasiatic family. More recent research instead suggests that the people of the Kerma culture spoke Nilo-Saharan languages of the Eastern Sudanic branch, and that the peoples of the C-Group culture to their north spoke Cushitic languages. They were succeeded by the first Nubian language speakers, whose tongues belonged to another branch of Eastern Sudanic languages within the Nilo-Saharan phylum. A 4th-century victory stela commemorative of Axumite king Ezana contains inscriptions describing two distinct population groups dwelling in ancient Nubia: a "red" population and a "black" population.