Complex sentence: The Mausoleum of Hadrian, usually known as the Castel Sant'Angelo, is a towering cylindrical building in Rome, central Italy, initially commissioned by the Roman Emperor Hadrian as a mausoleum for himself and his family.
Split into simpler sentences: The Mausoleum of Hadrian, usually known as the Castel Sant'Angelo, is a towering cylindrical building in Rome. It was initially commissioned by the Roman Emperor Hadrian as a mausoleum for himself and his family.