Editing Pope Pius VIII (section)

==Episcopate and cardinalate==
On 11 August 1800 Castiglioni was appointed [[Roman Catholic Diocese of San Benedetto del Tronto-Ripatransone-Montalto|Bishop of Montalto]]. He received [[episcopal consecration]] on 17 August in Rome at the Church of [[Santi Domenico e Sisto]]. Cardinal [[Giuseppe Doria Pamphili]] served as consecrator, assisted by [[Nicola Buschi]] and [[Camillo Campanelli]]. He refused to swear allegiance to [[Napoleon]] or to his client state, the [[Kingdom of Italy (Napoleonic)|Kingdom of Italy]]. On 29 July 1808 he was arrested and taken to [[Milan]]. Castiglioni was subsequently taken to [[Pavia]], to [[Mantua]], and then to [[Turin]], where he arrived on 10 November 1813. On 18 November he was brought back to Milan. Finally, after Napoleon fell, Castiglioni returned to his diocese on 16 June 1814.<ref name="CASTIGLIONI, Francesco Saverio (1761–1830)"/> He was praised by [[Pope Pius VII]] who in 1816 elevated him to the cardinalate as the Cardinal-Priest of [[Santa Maria in Traspontina]]. He held various high offices thereafter, including that of [[Apostolic Penitentiary]]. He soon became a [[Cardinal (Catholic Church)|Cardinal-Bishop]] of the suburbicarian see of [[Roman Catholic Suburbicarian Diocese of Frascati|Frascati]].

Castiglioni was considered a front-runner in the [[Papal conclave, 1823|conclave of 1823]]. He was known to be close to Pius VII, who often referred to Castiglioni as "Pius VIII".<ref>Pirie, Valérie. [http://www.pickle-publishing.com/papers/triple-crown-leo-xii.htm LEO XII (DELLA GENGA)] ''Pickle Pushing.'' Web. Retrieved 28 February 2016.</ref> However, he failed to gain the necessary votes, in part due to controversy surrounding an alliance between him and another [[Papabile|favorite]], Secretary of State [[Ercole Consalvi]]. Annibale Cardinal della Genga was elected instead, and he took the name of [[Pope Leo XII]]. Leo XII stated that Castiglioni would one day be called "Pius VIII".<ref>{{Cite web |title=Pope Pius VIII: Proceedings of the Conclave that led to his election. |url=https://www.pickle-publishing.com/papers/triple-crown-pius-viii.htm |access-date=2025-05-02 |website=www.pickle-publishing.com}}</ref>