John V was the son and successor of Sergius IV

Sergius IV of Naples

Sergius IV was Duke of Naples from 1002 to 1036. He was one of the prime catalysts in the growth of Norman power in the Mezzogiorno in the first half of the eleventh century...

 as Duke of Naples from 1034 until his death.

In 1034 Pandulf IV of Capua

Pandulf IV of Capua

Pandulf IV was the Prince of Capua on three separate occasions.From February 1016 to 1022 he ruled in association with his cousin Pandulf II. In 1018, the Byzantine catapan Boiannes destroyed the Lombard army of Melus of Bari and his Norman allies at Cannae...

 instigated a revolt in Sorrento

Sorrento

Sorrento is the name of many cities and towns:*Sorrento, Italy*Sorrento, Florida, United States*Sorrento, Louisiana, United States*Sorrento, Maine, United States*Sorrento, Victoria, a township on the Mornington Peninsula, Victoria, Australia...

 and annexed it to Capua. In the same year, Sergius IV's sister died and her husband, Rainulf Drengot

Rainulf Drengot

Rainulf Drengot was a Norman adventurer and the first count of Aversa .When one of Rainulf's numerous brothers, Osmond, was exiled by Richard I of Normandy for the murder of one of his kin, Rainulf, Osmond, and their brothers Gilbert Buatère, Asclettin , and Raulf went on a pilgrimage to the...

, returned to Pandulf's allegiance. Broken in spirit, Sergius retired to a the monastery of the Holy Saviour in insula maris, where the Castello del'Ovo now stands. He was succeeded by his son John V, who allied with Guaimar IV of Salerno

Guaimar IV of Salerno

Guaimar IV was Prince of Salerno , Duke of Amalfi , Duke of Gaeta , and Prince of Capua in Southern Italy over the period from 1027 to 1052. He was an important figure in the final phase of Byzantine authority in the Mezzogiorno and the commencement of Norman power...

, another enemy of Pandulf's. John was sent by Guaimar to Constantinople

Constantinople

Constantinople was the capital of the Roman, Eastern Roman, Byzantine, Latin, and Ottoman Empires. Throughout most of the Middle Ages, Constantinople was Europe's largest and wealthiest city.-Names:...

 to beseech the aid of the Byzantine Emperor. During his absence Sergius briefly came out of retirement to act as regent

Regent

A regent, from the Latin regens "one who reigns", is a person selected to act as head of state because the ruler is a minor, not present, or debilitated. Currently there are only two ruling Regencies in the world, sovereign Liechtenstein and the Malaysian constitutive state of Terengganu...

. Ultimately the emperor ignored his pleas. Sergius was back in his monastery by June 1036.

John did homage to Guaimar and remained faithful to him throughout his reign. In 1038 he founded a church a Naples dedicated to Saint Simeon, although its location is unclear.

Sources

• Chalandon, Ferdinand
  Ferdinand Chalandon
  Ferdinand Chalandon was a French medievalist and Byzantinist.Chalandon’s work remains the most substantial study of the Normans in Italy and though the details of what he wrote a hundred years ago have in places been modified, it remains the single most important work available to historians.Being...
  
  . Histoire de la domination normande en Italie et en Sicilie. Paris
  Paris
  Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
  
  , 1907.