In 1484, Riario was engaged in the war which broke out between the
Orsini and the
Colonna family, trying to secure in vain the life of his friend Lorenzo Oddone Colonna, who was charged of having murdered an Orsini and was executed by
Sixtus IV. In 1488,
Pope Innocent VIII sent Cardinal Riario as a legate to his maternal uncle
Girolamo Riario, at the time governor of
Forlì and
Imola, who was revolting against the
Holy See. Meanwhile, the Cardinal had already commissioned the erection of his palace beside the church of
San Lorenzo in Damaso (1486). It is said that
Franceschetto Cybo, the infamous son of
Innocent VIII, lost in one single night 15,000 ducats at a card game which took place in Raffaele's residence. When the
Pope asked the Cardinal to return his son's money, the latter answered that he was sorry, but he had already used it to finance the construction of his palace. As
Camerlengo, Riario is usually praised for ensuring order in
Rome after the death of Innocent VIII. He was a candidate for the papal tiara in the
Conclave of 1492, but excluded from the first ballots due to his young age. He finally voted for Rodrigo Borgia (
Pope Alexander VI), receiving the lucrative
Bishopric of Cartagena as a reward for his support. During
Alexander VI’s reign (1492–1503), Riario gained distinction as diplomat and councillor of the papal throne. In 1493, he was sent as legate to
Caterina Sforza, Girolamo Riario's widow, to prevent her from allowing the French troops to pass through Forlì and Imola.
Pope Julius II (1503–1513), Riario's relative but not always his ally, raised him to the
Bishopric of Ostia and Velletri. ==Engagement in the plot against Leo X and death==