Pius IX was the head of the Catholic Church from 1846 until his death in 1878, making his reign the longest verified papacy in history. Born Giovanni Maria Mastai-Ferretti in Senigallia, he initially gained a reputation as a liberal reformer. However, following the revolutions of 1848, his leadership became increasingly conservative. He is notably remembered for convening the First Vatican Council, which established the dogma of papal infallibility, and for his strong opposition to modernism and secularization during a period of significant political upheaval in Italy.