1-155-804 - Ann Ronan Picture Library/Heritage-Images

Pope Pius IX, 1846. Born Giovanni Maria Mastai Ferretti (1792-1878), Pius IX was elected Pope in 1846. His pontificate was the longest of the post-apostolic era. A conservative, Pius proclaimed the dogma of the Immaculate Conception in 1854, and in 1869 convened the First Vatican Council, which declared the doctrine of papal infallibility.