Editing Pope Clement X (section)

==Early work==
Altieri received a doctorate in law from the [[Roman College]] in 1611. After finishing his studies, he was named ''auditor'' of Giovanni Battista Lancellotti in 1623, in the [[nuncio]] of [[Polish-Lithuanian Commonwealth|Poland]]. He was ordained on 6 April 1624. On his return to Rome, he was named [[Bishop of Camerino]], then governor of [[Loreto (AN)|Loreto]] and of all [[Umbria]]. [[Pope Urban VIII]] (1623–44) gave him charge of the works designed to protect the territory of [[Ravenna]] from the unruly [[Po River]].<ref name=Loughlin/>

[[Pope Innocent X]] (1644–55) sent him as nuncio to [[Kingdom of Naples|Naples]], where he remained for eight years. He is credited with the re-establishment of peace after the stormy days of [[Masaniello]].<ref name=Loughlin/> [[Pope Alexander VII]] (1655–67) confided to him a mission to Poland.

[[Pope Clement IX]] (1667–69) named him Superintendent of the Papal Exchequer (in charge of the Church's finances), and in 1667 his ''maestro di camera'', and he was made Secretary of the [[Congregation of Bishops and Regulars]].<ref name=Loughlin/> Just before his death, Clement IX made him a [[Cardinal (Catholicism)|cardinal]]. He was then about seventy-nine years of age; and Clement IX, when making him a member of the [[College of Cardinals|Sacred College]], said to him: "You will be our successor."

After the funeral of Pope Clement IX, sixty-two electors entered into [[Papal conclave, 1669–1670|conclave]] on 20 December 1669. Forty-two votes were necessary, and due to the rivalry between the French and Spanish factions, heated discussion prevailed for four months. Cardinal [[Giannicolò Conti]] was supported by twenty-two votes; Cardinal [[Giacomo Rospigliosi]], nephew of the late pope, had thirty, or, as some say, thirty-three, with two at the ''accesso'', so that he needed only seven more votes to gain the [[papal tiara|tiara]]. Cardinal Carlo Cerri obtained twenty-three votes.

At length the cardinals agreed to resort to the old expedient of electing a cardinal of advanced years, and proposed Cardinal Altieri, almost an octogenarian, whose long life had been spent in the service of the [[Catholic Church]], and whom Clement IX, on the eve of his death, had raised to the dignity of the purple. The reason a [[prelate]] of such transcendent merits received the cardinalate so late in life seems to have been that he had waived his claims to the elevation in favour of an older brother.<ref name=Loughlin/>