In 1429, Prince Centurione was besieged inside the castle of Chalandritsa by the forces of Thomas Palaiologos. John dispatched a messenger with the name John Balotas to Constantine Palaiologos (who would become the last emperor of the eastern Roman empire) to declare that John preferred to hand over Chalandritsa to Theodora Tocco, wife of Constantine, as she was a sister of his spouse Magdalene Tocco and he preferred to give the castle to Constantine rather of Thomas. Constantine refused the offer stating that this could result in unnecessary fighting between the Palaiologoi brothers.^[5]

In the same year, Centurione was forced to surrender Chalandritsa to Thomas and give him the hand of his daughter Catherine Zaccaria to marry. Thomas as a husband of Catherine was to inherit all of his lands after his death. During the arrangements, Centurione ensured that his heir John would retain his princely title even only by name..^[6] He died in 1432 and the last remnants of the principality of Achaea passed to the despotate of Morea. The mother of John, a lady of the Asen-Palaiologos houses was imprisoned at Chlemoutsi, where she spend the rest of her days.^[7]

In 1446 John made his first attempt to restore the principality of his father, during the great invasion of Sultan Murad in Morea. It seems John had allies among the Greek nobility of Morea so when a Byzantine magnate rose in rebellion against the Palaiologoi brothers Thomas and Demetrios he proclaimed John as Prince of Achaea. However the rising failed its purpose and John along with his eldest son was imprisoned in the Chlemoutsi castle by Thomas Palaiologos..^[8] Thomas was his brother in law as he was married with Catherine Zaccaria, the sister of John. It was rumoured that Thomas allowed the last men of the Zaccarias dynasty to die of hunger, but against his designs they remained alive. On 1453 John and his son Antonio escaped Chlemoutsi^[9] after persuading their gaoler to release them. They took advantage of a widespread revolt against the Despots and seized the castle of Aetos, which raised the flags of Zaccarias.^[10]

The Byzantine contemporary historian George Sphrantzes recorded the renovation of the Principality in the following short passage: "At Morea, the brother in law of Thomas, the son of Prince Centurione, had escaped from the prison of the Chlemoutsi Castle causing disruption to the region, while the Sultan was concentrated against Serbia"^[11].

The Venetian Doge Francis Foscari and King Alfonso V of Naples sent John congratulation letters, recognising him as "Prince Centurione III".^[8] The recognition of Johns title by the Crown of Naples was a gesture of great importance since the sovereigns of Naples were the nominal overlords of the Principality of Achaea following the Viterbo treaty of William of Villehardouin and Charles of Anjou at 1267. John also requested from the sultan recogniton as Prince of Morea but Mehmed reinforced the Palaiologoi brothers.^[12]

John achieved the support of many Latins, Greeks, and Albanians and with them compromising his army, he besieged the city of Patras under Thomas's rule. However, after Turahan Bey invaded Morea he abandoned the siege and retreated in Aetos.^[13] In 1454, faced with the united forces of Despot Thomas and his Turkish allies he abandoned the fortress and fled to the Venetian stronghold of Modon. The city of Aetos submitted and the terms were that it would provide one thousand slaves to the army, weapons, and pack animals.

In the Venetian-held Modon he remained for two years. In 1456 we find him a pensioner of his supporter King Alfonso at Naples. Later in 1457 the Venetian Republic recognising his high political value as titular Prince of Morea granted him an annuity, on the condition John would continue to reside in Modon or wherever else he could be most useful to the designs of Venice. Seven years later, in 1464, after the complete annexation of Morea to the Ottoman empire, we find John moving to Rome where he managed to secure only a monthly pittance from Pope Paul II. He remained in the Papal capital until he died in 1469.^[10] John was also acknowledged as Prince of Achaea by the city of Genoa, where he endowed a precious reliquary of house Zaccaria, the so-called Zaccaria Cross that presumably contained pieces of the True Cross belonging to St John the Evangelist.^[14]

John married a woman named Magdalene. Sphrantzes notes that the wife of John was a sister of Theodora Tocco, wife of Constantine XI Palaiologos, calling the two men as "brothers in law", thus Magdalene was a member of the house Tocco and a daughter of Leonardo II Tocco.^[15] She is also attested in a letter addressed to her husband by the King of Naples Alfonso V of Aragon. In this she is mentioned as "the most majestic woman Magdalene Asenina Zaccaria" (having adopted the family names of John) and also receives recognition of her title as Princess of Achaea.^[16] Together they had at least three children:

1. An eldest son (Antonio?). He was imprisoned along with his parents at the Chlemoutsi fortress and later in 1453 escaped. He participated in the uprising of his father and then followed him in exile.
2. Angelo?.
3. Unnamed daughter. She was given as wife to the lord of Chlemoutsi. He agreed to release John from prison and joined him in his uprising.^[17]

• Miller, William (1908). The Latins in the Levant: A History of Frankish Greece (1204–1566). London: John Murray. OCLC 563022439.
• Topping, Peter (1975). "The Morea, 1364–1460". In Setton, Kenneth M.; Hazard, Harry W. (eds.). A History of the Crusades, Volume III: The Fourteenth and Fifteenth Centuries. Madison and London: University of Wisconsin Press. pp. 141–166. ISBN 0-299-06670-3.