[1] As a young man, Nardini served in the military, before joining the ecclesiastical estate and traveling to Rome.
[1] He then served as Pius II's nuncio to Germany; the pope wrote to him on 15 July 1459 about the advance of the Ottoman Empire in the Kingdom of Bosnia.
[1] He then served as a nuncio in the Kingdom of Aragon, in which capacity he successfully sought the derogation of a pragmatic sanction that endangered the freedom of the church.
[1] In the consistory of 7 May1473, Sixtus IV made Nardini a cardinal priest; he received the red hat and the titulus of Sant'Adriano al Foro (a deaconry elevated pro illa vice to titulus).
[1] On 10 June 1476 he accompanied the pope to Viterbo, and later to Foligno, because of an outbreak of bubonic plague in Rome.