Cardinal Colonna played a visible role in the Sack of Rome, with a group of mercenaries and peasants from the Colonna fiefs in Lazio and elsewhere, ultimately amounting to more than 8,000 men. They came up from Lanuvium, by way of the Porta S. Paolo. The Cardinal was accompanied by his half-brother Giacomo. Camillo Colonna, the son of Cardinal Pompeo's eldest brother, led the street fighting as far as the Orsini stronghold at Monte Giordano. Cardinal Pompeo took up residence in the Cancelleria Palace, which had been his when he was Vice-Chancellor. It was reported that the Cardinal sheltered his fellow cardinals Della Valle, Cesarini and Siena, who had bribed the Imperialists to leave their palaces untouched, but who fell victims anyway to the Landsknechten. He also sheltered more than 500 nuns, crowded (it is most incredibly said) in a single room. It was alleged that one of the nephews of Cardinal Colonna participated in the sack of a convent and rape of the nuns. On 10 May Cardinal Pompeo was put in command of the part of Rome immediately in front of the Castel S. Angelo, the rione of the city called "Ponte", and the Ponte Molle.