Complex sentence: The Vandal kingdom allowed the creation of other Romano-Berber states at the borders, but fell a century later, conquered by the Byzantine empire, who established an African prefecture, and later the Exarchate of Carthage.
Split into simpler sentences: The Vandal kingdom allowed the establishment of other Romano-Berber states at the polity's boundaries. The Byzantines established an African prefecture, and later the Exarchate of Carthage.