Now we enter the urban organism of Rome, the Eternal City, the city of classical architecture par excellence, where the past constantly mixes with the present and is tangible at every step of the tourist or scholar; this is the city of the twins Romulus and Remus raised by the she-wolf, which turned into a Republic and then became the Empire of the Caesars. The advent of Christianity saw it dotted with churches and new landmarks, committed to rooting the power of the popes in Italy and in the rising Europe. Popes were the first promoters of the rediscovery of the city’s classical past and monumental architecture, which exuded identities to be rescued and adjusted according to the tastes and inspirations of the great Renaissance artists.