The Duchy of Naples was a de facto independent state in southern Italy from 840 to 1123, when it became incorporated into the Kingdom of Campania as a Royal Fief under the direct control of the King.
History (Post Hastings)
In 1074, when hostilities flared up between Richard I of Capua and Robert Guiscard, Duke of Apualia and Calabria, Sergius V of Naples was caught between the two lords. After his nominal liege, Gisulf II of Salerno, declared for Robert, Sergius took the opportunity to free himself and launched a rebellion against him, with the support of Richard I and the Pope. While the war between Robert and Richard ended in stalemate, Sergius's campaign in Salerno ended in his full conquest of the Principality and its lands, although the majority of the wealth pillaged was immediately sent to Capua to assure an alliance. This brought the zenith of Salerno to a close. Sergius V eventually retired to a monastery in 1078, where he died soon after.
Sergius's son, Gregory V, throughout his reign enriched the Duchy of Naples through trade, in particular with the Byzantines. Through this, he eventually managed to officially secede Naples peacefully from the Byzantine Empire. Gregory's alliance with Capua eventually came to an end in 1099, when the ambitious Lombard count Lando, who desired to recreate the Principality of Beneveto and raised the citizenry against Norman rule, fell out with the Greek lord and demanded Salerno. Gregory V managed to defeat Lando in the field, and established Count John I of Capua as his vassal.
Sergius VI, sometimes referred to as the Pius, managed to transform Naples into the Kingdom of Campania through sheer martial strength. Upon ascending to the throne after the death of Gregory V, which has been speculated to be due to poisoning, Sergius organized his vassals and nobility and organized a mass conversion to Catholicism from Orthodoxy. This gained the support of the mostly Catholic citizenry and put Sergius in the good graces of Pope Honorius II, and hence gained him the de facto protection of the Holy Roman Empire. This protected him from the Normans to the south. Sergius campaigned in Sardinia, managing to force the island's numerous counties into vassalhood; he then established a feudal contract to maintain control called the Dominus Codex. This codex, written in 1123, granted Sergius VI the title King of Campania and ended the Duchy of Naples as a political entity.
List of Dukes of Naples (Post Hastings)
- Sergius V (1052-1078)
- Gregory V (1078-1115)
- Sergius VI (1116-1123) (Reign ended when crowned, became Sergius I of Campania)