Giulia, as his only legitimate child, succeeded him as Sovereign Duchess of Camerino, after being received the formal investiture from Pope Clement VII.

On 14 December 1527, an agreement was signed in Todi according to which, upon reaching marriageable age, Giulia was to marry Guidobaldo and bring a dowry of 30,000 ducats.

[4][7] The marriage of Giulia da Varano and Guidobaldo II della Rovere produced two children: the first one died shortly after birth,[8] and the second was a daughter, Virginia Feltria (born 17 September 1544 – died February 1571), who later married firstly in 1560 with Federico Borromeo, Count of Arona (nephew of Pope Pius IV), and secondly in 1569 with Ferdinando Orsini, Duke of Gravina.

Giulia da Varano died on 18 February 1547 aged 23 at Fossombrone and was buried in the church at the Monastery of Santa Chiara in Urbino.

[4][9] The Portrait of Giulia da Varano della Rovere by Titian around 1545–1547 is currently kept at the Galleria Palatina e Appartamenti reali in the Palazzo Pitti, Florence.