The siege of Naples was a siege in 1191 during the expedition of Henry VI, Holy Roman Emperor aiming to conquer the Kingdom of Sicily in name of the claim of his wife Empress Constance. It lasted three months before Henry abandoned his expedition, after suffering a heavy loss due to disease. After his retreat, the Sicilians set a counterattack that almost reconquered his conquests and captured Empress Constance. It was particularly rare in the history of war that an empress was captured in an imperial offensive campaign.