[2] After marrying into the noble Orsini family in the Papal States, Farnese soon acquainted herself with, and initiated an affair with, the Spanish Cardinal Rodrigo de Borja.

[3] Giulia Farnese was born in Canino, then within the Papal States, to Pier Luigi I Farnese (c. 1435 - November 1487), Lord of Capodimonte, Musignano, Valentano, Gradoli, Piansano, Canino and Abbazia al Ponte, Papal Vicar of Canino in 1466, and his wife (Ischia, March 1464) Giovanna called Giovannella Caetani of the Dukes of Sermoneta,[4][3][4][5] a member of the Caetani family which had produced Pope Gelasius II and Pope Boniface VIII, and paternal granddaughter of Ranuccio Farnese the Elder, and wife Agnese Monaldeschi.

At the age of fourteen, Giulia was sent to Rome by her mother in order to complete an education in the hopes of integrating herself into the Roman aristocracy.

[3][8] Orsini, who was described as being squint-eyed and devoid of any meaningful self-confidence, was the son of Adriana de Milà, a third cousin of Cardinal Rodrigo Borgia, who was then Vice-Chancellor of the Church.

According to Maria Bellonci, it is uncertain when Rodrigo Borgia (Pope Alexander VI) fell in love with Giulia and decided to make her his mistress.

What is known is that Adriana de Mila eventually gave her approval to Rodrigo Borgia and Giulia Farnese's relationship in order to win a higher status for her son within the Vatican.

The affair was widely rumored among gossips of the time, and Giulia was referred to as "the Pope's whore" or sarcastically as "the bride of Christ".

Records from the Apostolic Chamber from autumn of 1500 put Alessandro's annual income at just two thousand ducats, making him one of the poorest members of the Sacred College.

Whatever the case may be, Giulia claimed that Laura was indeed the Pope's daughter, but this may have been to raise the status of the child for future marriage considerations.

Giulia was captured by the French captain Yves d’Allegre, who demanded from the Pope, and received, a ransom of 3,000 scudi for her safe conduct to Rome.

In the first years of her widowhood, after a series of lovers whose names have not been recorded, she married Giovanni Capece-Bozzuto, Baron of Afragola and Lord of Balsorano, Patrician of Naples, a member of the lower ranking Neapolitan nobility.

[3] In early 1524, Giulia, apparently sensing that death was near, had her testament written on 14 March in her room, overlooking the church of San Girolamo, in the Arenula district of Rome.