The Papal conclave of 1846 was held in the Vatican following the death of Pope Gregory XVI. The conclave was necessitated by the urgent political and social changes sweeping through Europe, where calls for reform and national unification were growing. Giovanni Maria Mastai Ferretti, an archbishop from the Diocese of Imola, was elected as pope and took the name Pius IX. His papacy commenced amidst increasing demands for liberal reforms, yet it positioned him to engage with a rapidly changing world.

Pope Pius IX's tenure was marked by significant events including the Italian unification, the non-expedit of the Church regarding political involvement, and the proclamation of the dogma of the Immaculate Conception. His early years were characterized by a more liberal approach, where he welcomed modern ideas and opened the Church to engagement with contemporary society. Nevertheless, the Revolutions of 1848 challenged his authority, leading to a retreat from his earlier policies. He fled Rome for a short period, returning after being reinstated with French military support.

As Pius IX's papacy continued, he became increasingly conservative, culminating in the First Vatican Council's declaration of papal infallibility in 1870, which solidified the pope's authority over spiritual and geographic matters for his followers. He was recognized for his responses to contemporary challenges, delineating the role of the Church in a modern world and its interactions with the rapidly evolving political landscape across Europe thereby transforming papal authority for future generations.