Alexander VI was a keen businessman, and the region around Gandía was a major centre of sugarcane production where buying up lands of the cash-strapped local nobility was a smart plan.

Still, the pope was relentless in this pursuit: he managed to get the new King of Naples, Alfonso II to grant the fiefdom of Tricarico and the counties of Carinola, Claramonte and Lauria, worth 12,000 ducats a year, to Giovanni on the occasion of his coronation in May 1494.

[6] At this point, Giovanni Borgia was effectively a pawn in the hands of the Catholic Monarchs as his presence in Spain guaranteed the alliance between the House of Aragon and the papacy against the French.

[7] The pope had great plans for his favourite son, and entrusted him with the campaign against the powerful Orsini family who controlled a large part of the Roman Campagna and had sided with the French against Alexander VI in the previous years.

[9] At the Battle of Soriano "the men of the Church succumbed with great dishonor and loss", as Burchard put it in his diary; some five hundred soldiers were killed and many more were wounded, the Orsini captured all the cannons and scattered the papal forces.

According to Burchard he was last seen alive when he left a family dinner at the home of his mother, Donna Vannozza who owned a house near the Church of San Pietro in Vincoli.

The Pope was much disturbed by the news, but tried to persuade himself that the duke was enjoying himself somewhere with a girl and was embarrassed for that reason at leaving her house in broad daylight, and he clung to the hope that he might return at any rate in the evening.

[12]On the morning of 15 June, the servant Giovanni had ordered to wait for him at the Square of the Jews was found fatally wounded and unresponsive, and despite being taken into a house and given care, could neither be saved nor give any account of his master's fate before dying.

He had been lying in his boat on the Tiber on the night of the murder to guard his wood and watched as five men had thrown a corpse into the river next to the fountain at the Hospital of Saint Jerome, where refuse was usually disposed of.

When the death of the duke was officially announced, many Italian and foreign dignitaries expressed their condolences to the pope including such well-known enemies as Cardinal Giuliano della Rovere and Girolamo Savonarola.

[20] The corpse of the duke was first brought to Castel Sant'Angelo, then on the same evening, it was transferred to the Basilica of Santa Maria del Popolo, the favourite church of the Borgias, preceded by 120 torchbearers and many prelates and servants.

"This morning I was told by a trustworthy person that at this time His Beatitude has very close news of the truth, but he will pretend otherwise to surprise the authors in their sleep, as they are very important people and of high status", the Florentine envoy, Alessandro Braccio reported on 23 June.

But these sources describe events which happened after the death of Pope Alexander VI, when Cesare had already lost his principality, and was arrested in Naples by Gonzalo Fernández de Córdoba in May 1504.

One contemporary diplomatic despatch on 18 June 1504 claimed that "the wife of the Duke of Candia, who was killed by Valentino, procured this act of retribution and revenge, and she is a relative of the King of Spain.

[43] The same verdict was previously reached by Konstantin von Höfler, who stated that Cesare had no real reason for the murder, and that the pope's behavior makes this conjecture completely unrealistic.

Among the English, William Roscoe was of the same opinion, having established that the only really useful source for the murder was Burchard, and "throughout the whole narrative, there is not the slightest indication that Caesar had any share in the transaction"; on the fateful night the Duke of Gandía might have been "detected by some jealous rival, or injured husband, and had paid with his life the forfeiture of his folly", he assumed.

Directed by the pope, Cesare wrote a strongly worded letter to his younger brother: No matter how much joy and happiness I felt for my promotion to the cardinalate, although it was great, my anger was still greater when I heard of the bad reports that His Holiness Our Lord had received of you and your bad behaviour; because they have informed His Beatitude that you had been going around Barcelona at night killing dogs and cats, often visiting the brothel, gambling much money, speaking improperly and imprudently to important people, not obeying Don Enrique and Doña María [his father and mother-in-law] and finally acting in a way truly unworthy of a gentleman of your position.

[49] After taking possession of the Duchy of Gandía on 4 December 1493, Giovanni tried to placate his furious father, and diligently completed the tasks assigned to him, including the procurement of floor tiles for the Borgia Apartments of the Apostolic Palace and the restoration of Castel Sant'Angelo.

It was a sign of this friendship that they rode together during an excursion of the papal court through the city to Saint John Lateran on 5 May 1493 when Giovanni Borgia was conspicuously dressed in Turkish robes.

[51] The poem plays on the apostolic title of the pope as fisher of men alluding to the scandal when his son's body was dragged from the river: Piscatorem hominum ne te non Sexte putemus / Piscaris natum retibus ecce tuum Lest we do not think you are not a fisher of men, Sixth, you fish for your own son with nets The most important Renaissance literary work remembering the event was a traditional Hispanic ballad (romance) entitled Muerte del duque de Gandía (Death of the Duke of Gandía).

Even the oldest version, from a chapbook printed in Burgos around 1530, appeared more than thirty years after Juan's death, which suggests that the ballad had previously been transmitted by oral tradition for a long time.

D'Azeglio made Cesare Borgia an antihero who, among his many other crimes, threw the corpse of his brother into the Tiber, "washed off the blood-stains from the pommel of his saddle, and disappeared in a dark lane".

[55] Nikolaus Lenau, one of the most important German poets of the Late Romantic era dedicated a song, "Vater und Sohn" to Giovanni Borgia's murder in his 1837 epic, Savonarola.

The young duke is not sleeping in the arms of a prostitute, as his doting father thinks: Diesmahl hat eine alte, kühle, / Unsaubre Dirne ihn umfasst; / Er hält auf ihrem schlechten Pfühle vom Liebestaumel tiefe Rast.

[57] One of Dumas' early historical novels, it was based on documentary research, probably conducted with the collaboration of Pier Angelo Fiorentino, an Italian author whom he had met in Naples.

Recounted along with another infamous Renaissance era crime, the murder of Duke Alessandro de' Medico by his cousin, the poem is concerned with the relationship between historical facts and historiography.

“And the cloak floated”In contrast to the sensationalism of the Romantic literary tradition, the 1926 novel of The Borgias or At the Feet of Venus by Vicente Blasco Ibáñez was based on modern scientific research.

[62] After painstakingly reconstructing the events, the narrator concludes that the accusations against Cesare are only malicious slander, and his brother was simply a young man, enjoying life, not realizing the dangers involved.

Émile Bertaux, who discovered the painting in 1908, claimed that it was commissioned by María Enríquez de Luna, Giovanni Borgia's widow, and it shows the murder of his husband ordered by his brother, Cesare.

[67] In the 2010 animated short film, Assassin's Creed: Ascendance, a fictionalised version of Juan's death is depicted at the hand of Cesare Borgia, who hires a prostitute to murder him.