Isabella often found herself torn between her native Kingdom of Naples and her marital home of the Duchy of Milan, causing her to suffer personal and political difficulties.

[2] Named after her paternal grandmother (who died in 1465), the princess was educated at the residence of the Dukes of Calabria in Castel Capuano, and one of her teachers was the poet and humanist Giovanni Pontano.

[2] The bride and groom were first cousins (Isabella's mother and Gian Galeazzo's father were siblings), so a dispensation was needed, which was easily obtained from Pope Sixtus IV.

On 13 January 1490, in the Sala Verde of the Castello di Porta Giova, a masque or operetta entitled Il Paradiso, with a libretto by Bernardo Bellincioni was staged on the occasion of the wedding of Isabella with Gian Galeazzo.

In addition to the acknowledgment of her physical appearance, Isabella was also noted for having an energetic personality; Gian Galeazzo, on the other hand, was quite a contrast to his wife; he was pale, studious and melancholy.

[21] In April 1490, reports of Isabella's continuing virginity even reached the Hungarian court to her aunt, Queen consort Beatrice of Aragon.

[26][27] This worried Ludovico, since the birth of the heir could made Gian Galeazzo and Isabella as potential figureheads for opposition to his position as Regent, which he was unwilling to relinquish.

In order to weaken any coup attempts made by Isabella and her husband, Ludovico had her Neapolitan retinue returned home and restricted the young Duchess from appointing and rewarding followers.

[28] Despite the initial good understanding between Isabella and Beatrice,[b] soon aroused serious disputes over precedence: despite being the Duchess consort and thus the highest ranking woman at the Milanese court, Isabella was displaced by Ludovico's wife: Leonardo da Vinci was active in creating pageants and decorations in honour of Beatrice, and she was even given a political role, acting as ducal ambassador to Venice in 1493.

[34] King Ferdinand I of Naples, informed on the matter, replied that it was impossible that Isabella had tried to poison Galeazzo, who was "loved by them as a son and always proved to be a good servant and relative"; as for Rozone, he justified the behavior of his granddaughter, saying indeed that he was surprised that "out of desperation" he had not done worse.

Understanding the weight of this threat, Ludovico severed diplomatic ties with the Neapolitan court and built an alliance with Maximilian I, Holy Roman Emperor.

[39] This quote has particular relevance when observing that the fall of Naples was not the only tragedy to befall her at this time: the sickly Gian Galeazzo experienced a relapse of his stomach ailments, which, after several days of agony, led to the death of the young Duke on 21 October 1494.

In February 1495 she gave birth to her youngest daughter, Bianca Maria (named after Isabella and Gian Galeazzo's grandmother Bianca Maria Visconti);[48] ten months later, on 18 December, Isabella's father, King Alfonso II of Naples (who already abdicated in favor of his son on 23 January), died, and on 7 September 1496 her brother and new King Ferdinand II of Naples followed their father to the grave.

[50] However, any satisfaction that Isabella could have gained from witnessing the downfall of her rival was minimised; the Dowager Duchess petitioned Louis XII to name her son Duke of Bari, a title that belonged to the Sforza family.

In mid-February 1500, she stayed in Rome with her illegitimate half-brother Alfonso of Aragon, Duke of Bisceglie, husband of Lucrezia Borgia, daughter of Pope Alexander VI.

Isabella then tried to fight for the restoration of his son's rights over the Duchy of Milan, with the help of her sister-in-law Bianca Maria (Queen consort of the Romans as wife of Maximilian I), which, however, ultimately ended in failure.

She spent her spare time working on music and literature; the writer Amedeo Cornale was summoned to her court, which witnessed the printing of Bari's first book.

[61]Keeping in mind her previous life experiences, Isabella also made it her priority to enhance the defences of the Castello Normanno-Svevo, ensuring that it was up to date with the form of warfare that had harmed Milan and Naples.

Aside from building up defences, the situation in Milan had taught the Duchess that political security was also essential; her will needed to be upheld at all times, never weakened or undermined.

[69] In January 1512, the Duchess learned of the tragic death of her son Francesco Maria, who died after falling from a horse while hunting in Angoulême, France.

[71] Initially, Isabella desired for Bona Maria to wed her cousin Ercole Massimiliano Sforza (who stayed in Innsbruck at the court of Holy Roman Emperor Maximilian I) in the hope of uniting their two rival branches of the family,[5] and also with the purpose to give her daughter power in Milan.

At the end, Ercole Massimiliano's control over the Duchy of Milan proved too weak at this point and the French took it over once again in the aftermath of the Battle of Marignano on 13 September 1515.

[75][76] The contract was signed on the day, according to which Isabella was to pay King Sigismund I 100,000 pure gold ducats, 50,000 of which would be paid shortly after Bona Maria's arrival in Poland, and the other half within the next two years.

[93] Ambrogio da Corte, one of the courtiers charged with leading her from Naples to Milan, even describes her as "ugly, black, cross-eyed, too much made up, and her breath stinks":[92] probably exaggerates, but Isabella did indeed have a dark complexion, a thick and slightly hooked nose, the swollen cheeks typical of the Aragonese, and it is also possible that she had inherited a certain degree of strabismusfrom her father, since Alfonso II was called il Guercio.

[95] No doubt Isabella inherited from her Aragonese relatives the indomitable pride and combativeness, and was not afraid to resort to unfair means - such as poison - to achieve her goals,[96] but her biographers agree in attributing to her a certain will for justice and a certain capacity for good governance during the years of maturity in Bari,[97] Although not separated from some abuse of power against citizens: some of these accused her of "terribilitate et potentia" because she used to use "violentie et fraude".

The story appears unclear: a courtier, Moroleto (or Morello) Ponzone, told the Duchess of Ferrara that, meeting one evening the Dukes of Bari and those of Milan with the Marquise of Mantua and other friends playing cards, Isabella found herself sitting in front of "a beautiful corsiero", in such a way that "she always looked at him" and "she had no mind in the game except that courser", so that Moroleto, moved with compassion, took "a little presumption" and "with honesty and good words" took him away, keeping him engaged in chatter until the game ended and everyone went to sleep.

[100] However, the term is sometimes used metaphorically to indicate not the beast, but the one who rides it; moreover, Achille Dina strangely omits the final part of the letter, that is, the one from which it is understood to be a man, and not an animal, since otherwise it would not be possible to understand why Moroleto had to spend the rest of the evening conversing with a horse.

[99] Retired to live in the kingdom of Naples, Isabella had as her lover the leader Prospero Colonna, to whom "she gave herself in prey, enjoying and tickling lovingly almost every night".

So, "having Isabella broken the brake on lasciviousness and, of modesty that she was before, became immodest", she also took as a lover the young Giosuè de Ruggiero, a man of the low nobility born in the farmhouse of Marigliano, who had been amasio of the same Prospero Colonna.

Then, having retired to Bari, and having Giosuè remain in Naples, Isabella, although she was past forty, took as a lover the thirty-year-old Alessandro Pignatelli, lord of Toritto, who with his wife Laura della Marra already had many children.