The Sack of Rome, then part of the Papal States, followed the capture of Rome on 6 May 1527 by the mutinous troops of Charles V, Holy Roman Emperor, during the War of the League of Cognac. Charles V only intended to threaten military action to make Pope Clement VII come to his terms. However, most of the Imperial army were largely unpaid. Despite being ordered not to storm Rome, they broke into the scarcely defended city and began looting, killing, and holding citizens for ransom without any restraint. Clement VII took refuge in Castel Sant'Angelo after the Swiss Guard were annihilated in a delaying rear guard action; he remained there until a ransom was paid to the pillagers.