context: The number of troops defending Rome was not large, consisting only of 5,000 militias led by Renzo de Ceri and the Swiss Guard of the Pope. The city's defenses involve giant walls and a powerful artillery force which the Imperial forces cannot match. Charles III needed to take control of Rome quickly to avoid the risk of being trapped between the city defense forces that were under attack and the Cognac League troops who would definitely come to help.
question: How many troops defended Rome?
answers.text: 5,000 militias