His work as a diplomat in dealing with Duke Francis of Brittany and with Charles de France brought him the office of first minister to the King.

Secret correspondence revealed that he might have been playing both sides in the negotiation, and he was arrested, and held on charges of treason from 1469 to 1481, while King and Pope argued over jurisdiction.

The date of his birth is conjectured to be around 1421, based on his epitaph in Santa Prassede in Rome, in which he is said to have died as Legate of the Marches while in his seventies, Legatum agens septuagenarius gloriose obiit.

[7] In 1462 he accompanied Bishop de Beauvau to Rome in the embassy which was sent to present the homage of the new King of France, Louis XI, to Pope Pius II, and to engage in negotiations concerning the revocation of the Pragmatic Sanction, as well as the French claims to the Kingdom of Naples.

[10] On 10 February 1464, at the request of King Louis, the Pope granted Balue a new Canonry in the Cathedral Chapter of Angers which had fallen vacant.

But Bishop de Beauvau held a bull of Pius II which granted him the gift of an abbey or any other benefice which happened to become vacant.

[19] On 27 August the King granted Balue a subsidy from the gabelle to allow him to resume work on the restoration of the Cathedral, which had begun under the patronage of Charles VII but which had ceased from lack of funds.

In the War of the Public Weal (Bien Publique), Bishop Balue and Charles Melun were assigned to the task of defending the city of Paris for the King.

Whether true or not, Charles flatly refused the King's request and Balue had to give a completely negative report of the mission.

[22] At the end of the year Bishop Balue was sent back to Nantes, this time along with Guillaume de Paris, as Ambassadors of the King of France, to protest Louis' desire for good relations with Francis of Brittany, but to inquire about rumored dealings with the English.

Francis disavowed any sinister implications, but it was discovered that the Duke and Duchess of Savoy were in Brittany, negotiating a league against King Louis.

[23] King Louis IX made Bishop Jean Balue le premier du grant conseil.

Thomas Basin remarks that the King held Balue to be velut fidissimum omnium mortalium hominum amicum ('practically the most trusted friend in the world').

[31] But Balue shortly became compromised in the king’s humiliation by Charles the Bold at Péronne, as more and more important persons expressed disapproval of the treaty.

The King was intent on putting Balue on trial for treason before royal judges, and Louis appointed a commission of eight men to find out the truth and mete out the punishment; but that raised the old issue of the exemption of clerics from civil jurisdiction; a cleric could only be tried in an ecclesiastical forum in accordance with Canon Law, and that was the position of Pope Sixtus IV.

King Louis sent an agent to Rome, Pierre Gruel, a President of the Parlement of Grenoble to explain the situation to the Pope.

The ambassadors were received by the Pope on 1 December 1469, and a long series of discussions and debates ensued, which finally ended in an agreement to disagree as to who had the right and obligation to proceed against Balue.

In Angers the Vicars of Cardinal Balue remained loyal and resisted the pressures from the Cathedral Chapter and the King until 1472, when they renounced the exercise of their functions under threat of royal fines.

In March 1476 Pope Sixtus IV took the extraordinary step of relieving Bishop Jean de Beauvau of the various ecclesiastical censures which he had incurred, and returning his former benefices; his various acts were ratified.

[42] In June 1480, Cardinal Giuliano della Rovere was sent to France as Legate to make peace between Louis XI and Maximilian of Austria, as well as to negotiate the release of Balue and Harancourt.

He reached Paris in September, and finally, on 20 December 1480, King Louis gave orders that Balue be handed over to the Archpriest of Loudun, who had been commissioned by the Legate to receive him in the name of the Pope.

On 31 January 1483, Pope Sixtus named Cardinal Balue suburbicarian Bishop of Albano,[45] making clear to all where his sympathies lay.

Della Rovere and Balue were met at the gate of Rome by nearly all the Cardinals on 3 February 1483, and shortly thereafter were received in public Consistory.

[50] In February 1485 Cardinal Balue was named French ambassador to the Court of Rome and Protector of France by King Charles VIII.

Envoys of Charles VIII and René reached Rome in May 1486, prepared to conclude negotiations, but the diplomacy of Ferdinand of Aragon, the operations of the condottiere Broccolino Guzzoli, and the appearance of Turkish ships in the Adriatic, put a stop to the French adventure.

[51] In 1485, following the wishes of Pope Innocent VIII, Cardinal Balue instituted the Feast of the Visitation in the diocese of Angers, to which, however, he never returned.

The Pope was his heir since the Cardinal had left no Last Will and Testament, and the rumor reported by Joannes Burchard, the Master of Ceremonies, was that he was worth some 100,000 ducats.