1823 conclave

A papal conclave was held from 2 to 28 September 1823 to elect a new pope to succeed Pius VII, who had died on 20 August. Of the 49 eligible cardinal electors, all but four attended. On the final ballot, the conclave elected Cardinal Annibale della Genga, the cardinal vicar of Rome. After accepting his election, he took the name Leo XII.

Pius VII, who had been elected in 1800, had an unusually long pontificate, during which the Catholic Church had faced, in the French Revolution and its aftermath, a severe attack on its power and legitimacy. Pius VII himself had been a prisoner of Napoleon in France for six years.