The northern towns of Sicily opened their gates to Henry, including the earliest Norman strongholds Capua and Aversa, as well as Sorella, Atina and Teano; Richard of Fondi, Roger of Molise and William of Caserta all joined the emperor.

On May the German army reached the wealthy and powerful Naples, where Henry VI met his first resistance in this campaign by its defender Aligerno Cottone and Richard of Acerra brother-in-law of Tancred.

The fortifications of Naples was strong enough to withstand the repeated attacks; Margaritus of Brindisi, in charge of a fleet of 72 galleys, also came to its aid and managed to harass the Pisan navy, thus keeping the harbor approaches open, so the line of the supply of the city would not be cut off.

After a siege of three months or six weeks, On August 15 Genoa sent out 33 galleys after Henry VI renewed his promises to call for their aid, but it was too late and Margaritus nearly destroyed them; at the same time the German army suffered from heat, malaria, dysentery, cholera and other epidemics that were aggravated by marshy air, and supply shortages.

Among them was Salerno, whose populace acted against Constance upon receiving letters from Nicholas before stopped by Sicilian army led by Elia di Gesualdo and Margaritus.

Henry and his younger brothers Conrad and Philip managed to return to Germany while his subject Dipold also successfully defended the rear from a bridgehead in the Terra di Lavoro, as Tancred was too hesitant that he missed the opportunity to annihilate the invading army.

Having no intention of killing the empress, Tancred locked her in Castel dell'Ovo surrounded by water in order to take her as a hostage in exchange for Henry VI's agreement to cease the war.