The 1806 Invasion of Naples by Napoleon's forces was provoked when King Ferdinand I of the Two Sicilies joined the Third Coalition against Imperial France. The Kingdom of Naples was rapidly overrun by Imperial soldiers, but Hesse stubbornly held out at Gaeta. The garrison put up such fierce resistance that a large part of Masséna's "Army of Naples" was tied up in the siege for nearly five months. This prevented Masséna from sending reinforcements to quell an uprising that had started in Calabria as well as allowing the British to land an expeditionary force and score a victory at the Battle of Maida. However, because the British failed to relieve the garrison of Gaeta, the city was finally captured in mid-July after French artillery smashed gaps in the city's defences.