Original: When the Caliphate was seized by the Abbasids, Al-Andalus (the Arab name for Hispania) split from the Abbasid Caliph in Baghdad to form their own caliphate.
Simplified: Later the caliphate was won by the Abbasids and Al-Andalus (or Hispania) split from the Abbasid Caliph in Baghdad to form their own caliphate.