Complex sentence: Vasak received the royal title from the Muslims at the end of his reign that lasted until 963; then the throne was inherited by his nephew Sembat (963-998) who was recognized king by the emirs of Tauris and of Arran.
Split into simpler sentences: Vasak received the royal title from the Muslims at the end of his reign which lasted until 963. The throne was inherited by his nephew Sembat (963-998) who was recognized king by the emirs of Tauris and of Arran.