[1] After the papal conclave, 1492, which elected Borja's relative Rodrigo pope as Alexander VI, he was created cardinal-priest of S. Susanna on August 31, 1492.
Borja was named bishop of Ferrara on October 29, 1494, taking possession of the see on June 14, 1497, until his death.
[1] In May 1494, he attended the coronation of Alfonso II of Naples, along with one patriarch, seven archbishops, and forty bishops; Borja himself crowned Alfronso king on May 18.
[1][2] Along with Cesare Borgia and Alexander VI, Juan met with Alfonso on July 12, 1494, in Vicovaro to co-ordinate military strategy against Cardinal Ascanio Sforza (whom Borja would later replace in the office of the Vice-Chancellor in 1500) and his allies as well as Charles VIII of France.
[3] He brought Alexander VI's terms of peace to Charles VIII on December 25, 1494, in Bracciano before retreating with the pontiff on January 7, 1495, to the Castel Sant'Angelo (and then on May 27, 1495, to Orvieto) to take refuge from French troops.