The city of Rome has been sacked several times during the last 2,000 years, most notably in the sixth century, by the Ostrogoths, who depopulated the city and burned it to the ground. It was occupied by foreign armies too numerous to count—the last being the Germans and Americans during World War II—but each time rose from the ashes, the Eternal City. The last great pillage of Rome occurred in 1527, when the Imperial army of Emperor Charles V overran the city and massacred the Swiss Guard protecting Pope Clement VII, who scampered to safety down the passetto di Borgo, the secret tunnel which still links the Vatican to Castel Sant’Angelo. Thousands were slaughtered, churches, shrines and monasteries burned to the ground, the papacy humiliated, the pope eventually imprisoned, and the population of Rome reduced to less than 10,000. Yet Rome would again rise, more prosperous, as a city of more than 100,000. The papacy was restored, and the city experienced a monumental spiritual and cultural transformation.