The Palatine Hill, which relative to the seven hills of Rome is the centremost, is one of the most ancient parts of the city; it has been called "the first nucleus of the Roman Empire". The site is now mainly a large open-air museum whilst the Palatine Museum houses many finds from the excavations here and from other ancient Italian sites. Imperial palaces were built there, starting with Augustus. Before imperial times the hill was mostly occupied by the houses of the rich.