John was the amiratus

Admiral

Admiral is the rank, or part of the name of the ranks, of the highest naval officers. It is usually considered a full admiral and above vice admiral and below admiral of the fleet . It is usually abbreviated to "Adm" or "ADM"...

or emir

Emir

Emir , meaning "commander", "general", or "prince"; also transliterated as Amir, Aamir or Ameer) is a title of high office, used throughout the Muslim world...

 of Roger II of Sicily

Roger II of Sicily

Roger II was King of Sicily, son of Roger I of Sicily and successor to his brother Simon. He began his rule as Count of Sicily in 1105, later became Duke of Apulia and Calabria , then King of Sicily...

. John was born to the Admiral Eugenius in Palermo

Palermo

Palermo is a city in Southern Italy, the capital of both the autonomous region of Sicily and the Province of Palermo. The city is noted for its history, culture, architecture and gastronomy, playing an important role throughout much of its existence; it is over 2,700 years old...

, where his family had moved from Troina

Troina

Troina is a town and comune in the province of Enna, Sicily, Italy. It is located in the Nebrodi Park.-History:...

. His brothers were the logothete

Logothete

Logothete was an administrative title originating in the eastern Roman Empire. In the middle and late Byzantine Empire, it rose to become a senior administrative title, equivalent to a minister or secretary of state...

Philip and the amiratus Nicholas. His uncle was the notary

Scrivener

A scrivener was traditionally a person who could read and write. This usually indicated secretarial and administrative duties such as dictation and keeping business, judicial, and history records for kings, nobles, temples, and cities...

 Basil. All his family members were closely connected to the royal family and in its service. John's son was the equally famous Eugenius II.

In 1131, John was sent across the Strait of Messina

Strait of Messina

The Strait of Messina is the narrow passage between the eastern tip of Sicily and the southern tip of Calabria in the south of Italy. It connects the Tyrrhenian Sea with the Ionian Sea, within the central Mediterranean...

 to join up with a royal troop from Apulia

Apulia

Apulia is a region in Southern Italy bordering the Adriatic Sea in the east, the Ionian Sea to the southeast, and the Strait of Òtranto and Gulf of Taranto in the south. Its most southern portion, known as Salento peninsula, forms a high heel on the "boot" of Italy. The region comprises , and...

 and Calabria

Calabria

Calabria , in antiquity known as Bruttium, is a region in southern Italy, south of Naples, located at the "toe" of the Italian Peninsula. The capital city of Calabria is Catanzaro....

 and march on Amalfi

Amalfi

Amalfi is a town and comune in the province of Salerno, in the region of Campania, Italy, on the Gulf of Salerno, c. 35 km southeast of Naples. It lies at the mouth of a deep ravine, at the foot of Monte Cerreto , surrounded by dramatic cliffs and coastal scenery...

 by land while George of Antioch

George of Antioch

George of Antioch was the first true ammiratus ammiratorum, successor of the great Christodulus. George was a Greek Melchite, born in Antioch, whence he moved with his father, Michael, and mother to Tunisia. His parents found employment under the Zirid Sultan, Tamim ibn Muizz...

 blockaded the town by sea and set up a base on Capri

Capri

Capri is an Italian island in the Tyrrhenian Sea off the Sorrentine Peninsula, on the south side of the Gulf of Naples, in the Campania region of Southern Italy...

. Amalfi soon capitulated.

In 1135, John and the chancellor

Chancellor

Chancellor is the title of various official positions in the governments of many nations. The original chancellors were the Cancellarii of Roman courts of justice—ushers who sat at the cancelli or lattice work screens of a basilica or law court, which separated the judge and counsel from the...

 Guarin

Guarin

Guarin was the chaplain and chancellor of Roger II of Sicily from about 1130 to his death, during the first decade of the Norman kingdom of Sicily. According to Alexander of Telese, the contemporary chronicler, he was "erudite ... and most prudent in negotiations .....

 were sent to Campania

Campania

Campania is a region in southern Italy. The region has a population of around 5.8 million people, making it the second-most-populous region of Italy; its total area of 13,590 km² makes it the most densely populated region in the country...

 and the Principality of Salerno

Principality of Salerno

The Lombard Principality of Salerno was a South Italian state, centered on the port city of Salerno, formed in 851 out of the Principality of Benevento after a decade-long civil war....

 to defend the royal castles against the general rebellion of Robert II of Capua

Robert II of Capua

Robert II was the count of Aversa and the prince of Capua from 1127 until his death .He was the only son and successor of Jordan II of Capua...

, Ranulf II of Alife, and Sergius VII of Naples

Sergius VII of Naples

Sergius VII was the thirty-ninth and last duke of Naples. He succeeded his father John VI on the Neapolitan throne in 1120 or 1123 at a time when Roger II of Sicily was rising rapidly in power...

. They successfully defended Capua

Capua

Capua is a city and comune in the province of Caserta, Campania, southern Italy, situated 25 km north of Naples, on the northeastern edge of the Campanian plain. Ancient Capua was situated where Santa Maria Capua Vetere is now...

 with 2,000 knights and a similar-sized complement of infantry, but Aversa

Aversa

Aversa is a town and comune in the Province of Caserta in Campania southern Italy, about 15 kilometres north of Naples. It is the centre of an agricultural district, the agro aversano, producing wine and cheese...

 fell to Robert.

Sources

• Norwich, John Julius
  John Julius Norwich
  John Julius Cooper, 2nd Viscount Norwich CVO — known as John Julius Norwich — is an English historian, travel writer and television personality.-Early life:...
  
  . The Kingdom in the Sun 1130-1194. London: Longmans, 1970.
• Curtis, Edmund. Roger of Sicily and the Normans in Lower Italy 1016–1154. New York: G. P. Putnam's Sons, 1912.
• Matthew, Donald. The Norman Kingdom of Sicily (Cambridge Medieval Textbooks). Cambridge University Press, 1992.
• Houben, Hubert (translated by Graham A. Loud and Diane Milburn). Roger II of Sicily: Ruler between East and West. Cambridge University Press, 2002.