Simplify the following text for a Grade 12 native English-speaking person.
Original: The origins of the taifas must be sought in the administrative division of the Umayyad Caliphate of CÃ rdoba , as well in the ethnic division of the elite of this state , divided among Arabs , Berbers , Iberian Muslims ( known as MuladÃ es - the overwhelming majority ) and the Eastern European former slaves .
Simplified: The reason that taifas developed was that there was an administrative division of the Umayyad Caliphate of CÃ rdoba and also an ethnic division of the elite of this state . It was divided among Arabs ( they werde a powerful but tiny minority ) , Berbers , Eastern European former slaves and Iberian Muslims ( known as MuladÃ es ( those were the great majority ) .