He came to power in 1846 as the progressive darling of the entire world, freeing political prisoners and throwing open the gates of Rome's Jewish ghetto. Thirty-two years later, he died a self-declared prisoner so hated that an angry mob nearly threw his coffin into the Tiber River.

This deep dive traces the staggering paradox of Giovanni Maria Mastai Ferretti, the last pope to rule as a literal secular king. We explore how betrayals, revolutions, and the loss of his earthly kingdom forced him to abandon liberalism and build the fiercely centralized spiritual papacy that still governs over a billion Catholics today.

• How an epilepsy diagnosis derailed his military career and pushed him toward the priesthood under the empathy of Pope Pius VII
• The dramatic 1846 conclave where allies pushed his vote through before an Austrian ...