Why did the Bourbon royal family flee Naples during Napoleon’s Italian campaign?

The Bourbon royal family, led by King Ferdinand IV and Queen Maria Carolina, fled Naples for Sicily on two separate occasions during the Napoleonic era due to the direct military threat posed by French forces.123

• 1798–1799: Following the outbreak of the War of the Second Coalition, Ferdinand IV—encouraged by the British fleet under Admiral Horatio Nelson—attacked the French-supported Roman Republic. In retaliation, French forces invaded Naples, leading the royal family to flee to Palermo aboard British ships.231
• 1806: After Ferdinand’s continued political maneuvering against France and his alliance with the Austrians, Napoleon grew exasperated. Following his victory at Austerlitz, Napoleon sent his brother, Joseph Bonaparte, to conquer the kingdom. Facing this invasion, the Bourbon court fled to Sicily once again, where they remained under British protection until the fall of Napoleon in 1815.1423

These flights were driven by the necessity of escaping French military occupation and the subsequent installation of Napoleonic rulers, such as Joseph Bonaparte and Joachim Murat, in the Kingdom of Naples.13