Pope IV, also known as Pope Paul IV, served as the head of the Roman Catholic Church from 1555 to 1559. He was born Giovanni Pietro Carafa in 1476 in Naples, Italy. His papacy is noted for its strict enforcement of Catholic doctrine and the establishment of the Roman Inquisition, which aimed to combat heresy. During his time as pope, Paul IV also implemented significant reforms within the Church, including the creation of the Index Librorum Prohibitorum, a list of prohibited books. His tenure was marked by tensions with Protestant reformers and political conflicts in Italy, particularly with the Spanish Empire.