Complex sentence: Santa Dorotea is a Roman Catholic church in the Diocese of Rome is an ancient church and is first attested to in a Papal bull of Pope Callistus II in 1123, being referred to under its first dedication of "San Silvestro alla Porta Settimiana".
Split into simpler sentences: Santa Dorotea is a Roman Catholic church in the Diocese of Rome. This is an ancient church and is first attested to in a Papal bull of Pope Callistus II in 1123, being referred to under its first dedication of "San Silvestro alla Porta Settimiana".