Complex sentence: Arete is sometimes described as the successor of her father as head of the Cyrenaic school, but in fact it is not known whether Aristippus himself or his grandson--also called Aristippus of Cyrene--was the founder of that school.
Split into simpler sentences: Arete is sometimes described as the successor of her father as head of the Cyrenaic school. But in fact it is not known whether Aristippus himself or his grandson--also called Aristippus of Cyrene--was the founder of that school.