The Sack of Rome on 6 May 1527 was a military event carried out by the mutinous troops of Charles V, Holy Roman Emperor in Rome, then part of the Papal States. It marked a crucial imperial victory in the conflict between Charles and the League of Cognac (1526–1529) — the alliance of France, Milan, Venice, Florence and the Papacy.
Pope Clement VII had given his support to the Kingdom of France in an attempt to alter the balance of power in the region, and free the Papacy from what many considered to be 'Imperial domination' by the Holy Roman Empire (and the Habsburg dynasty).
The army of the Holy Roman Emperor defeated the French army in Italy, but funds were not available to pay the soldiers. The 34,000 Imperial troops mutinied, and forced their commander, Charles III, Duke of Bourbon and Constable of France, to lead them towards Rome.
Apart from some 6,000 Spaniards under the Duke, the army included some 14,000 Landsknechts under Georg von Frundsberg, some Italian infantry led by Fabrizio Maramaldo, Sciarra Colonna and Luigi Gonzaga, and some cavalry under Ferdinando Gonzaga and Philibert, Prince of Orange.
Though Martin Luther himself was not in favor of it, some who considered themselves convinced followers of Luther's Protestant movement viewed the Papal capital as a target for religious reasons, and shared with the soldiers a desire for the sacking and pillaging of a very rich city that appeared to be an easy target. Numerous bandits, along with the League's deserters, joined with the army during the march.
The Duke left Arezzo on April 20, 1527, taking advantage of the chaos among the Venetians and their allies after a revolt which had broken out in Florence against the Medici. In this way, the largely undisciplined troops sacked Acquapendente and San Lorenzo alle Grotte, and occupied Viterbo and Ronciglione, reaching the walls of Rome on May 5.ceri
above Sack of Rome. May 6, 1527. By Martin van Heemskerck (1527).The troops defending Rome were not at all numerous, consisting of 5,000 militiamen led by Renzo di Ceri and the Papal Swiss Guard. The city's fortifications included the massive walls, and it possessed a good artillery force, which the Imperial army lacked. Duke Charles needed to conquer the city hastily, to avoid the risk of being trapped between the besieged city and the League's army.
On May 6, the Imperial army attacked the walls at the Gianicolo and Vatican Hills. Duke Charles was fatally wounded in the assault, allegedly shot by Benvenuto Cellini. The Duke was wearing his famous white cloak to mark him out to his troops, but it also had the unintended consequence of pointing him out as the leader to his enemies. The death of the last respected command authority among the Imperial army caused any restraint in the soldiers to disappear, and they easily captured the walls of Rome the same day. Philibert of Châlon took command of the armies, but he was not as popular or feared, leaving him with little authority. One of the Swiss Guard's most notable hours occurred at this time. Almost the entire guard was massacred by Imperial troops on the steps of St Peter's Basilica. Of 189 guards on duty only 42 survived, but their bravery ensured that Pope Clement VII escaped to safety, down the Passetto di Borgo, a secret corridor which still links the Vatican City to Castel Sant'Angelo.
After the brutal execution of some 1,000 defenders of the Papal capital and shrines, the pillage began. Churches and monasteries, as well as the palaces of prelates and cardinals, were looted and destroyed. Even pro-Imperial cardinals had to pay to save their properties from the amok soldiers. On May 8, Cardinal Pompeo Colonna, a personal enemy of Clement VII, entered the city. He was followed by peasants from his fiefs, who had come to avenge the sacks they had suffered by Papal armies. However, Colonna was touched by the pitiful conditions of the city and hosted in his palace a number of Roman citizens.
After three days of ravages, Philibert ordered the sack to cease, but few obeyed. In the meantime, Clement remained a prisoner in Castel Sant'Angelo. Francesco Maria della Rovere and Michele Antonio of Saluzzo arrived with troops on June 1 in Monterosi, north of the city. Their cautious behaviour prevented them from obtaining an easy victory against the now totally undisciplined Imperial troops. On June 6, Clement VII surrendered, and agreed to pay a ransom of 400,000 ducati in exchange for his life; conditions included the cession of Parma, Piacenza, Civitavecchia and Modena to the Holy Roman Empire (however, only the latter could be occupied in fact). At the same time Venice took advantage of his situation to capture Cervia and Ravenna, while Sigismondo Malatesta returned in Rimini.
Emperor Charles V was greatly embarrassed and powerless to stop his troops, but was powerless to stop his troops