Pius IX (1792-1878) was pope from 1846 to 1878. He began his reign devoted to liberal ideals but, embittered by the anticlericalism of Italian liberals and by the assault on papal territories by the new kingdom of Italy, became an important foe of progress and change.

Pius IX was born Giovanni Maria Mastai-Ferretti on May 13, 1792, at Senigallia, Italy. He became archbishop of Spoleto in 1827 and bishop of Imola in 1832. He was already recognized as a liberal when he was created a cardinal in 1840. On the death of Gregory XVI a conclave divided between progressive and conservative prelates chose, on June 16, 1846, Mastai-Ferretti as pope in preference to the reactionary Luigi Lambruschini.

The new pope began his pontificate--the longest in history--by initiating badly needed reforms. Improvements in financial administration and in the treatment of criminals in the Papal States were followed by an easing of the censorship. The political innovations of 1847 decreed...