Complex sentence: She was taught originally by her mother, Ersilia Cavallo, who was a pupil of Ferruccio Busoni, she went on to study under Alfredo Casella and Guido Agosti.
Split into simpler sentences: She was taught originally by her mother, Ersilia Cavallo, who was a pupil of Ferruccio Busoni. She went on to study under Alfredo Casella and Guido Agosti.