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Giovanni Mastai Ferretti, born on May 13, 1792, in Senigallia, Italy, was the birth name of Pope Pius IX, who served as the head of the Catholic Church from 1846 until his death in 1878. He was known for his conservative views and his opposition to liberalism and modernism within the Church. During his papacy, he convened the First Vatican Council, which defined the doctrine of papal infallibility.