The Italian Catholic Church, or Catholic Church in Italy, is part of the worldwide Catholic Church in communion with the Pope in Rome, under the Conference of Italian Bishops. The pope serves also as Primate of Italy and Bishop of Rome. In addition to Italy, two other sovereign nations are included in Italian-based dioceses: San Marino and the Vatican City. There are 225 dioceses in the Catholic Church in Italy, see further in this article and in the article List of Catholic dioceses in Italy. The pope resides in the Vatican City, enclaved in Rome. Having been a major center for Christian pilgrimage since the Roman Empire, Rome is commonly regarded as the "home" of the Catholic Church, since it is where Saint Peter settled, ministered, served as bishop, and died. His relics are located in Rome along with Saint Paul's, among many other saints of Early Christianity. Owing to the Italian Renaissance, church art in Italy is extraordinary, including works by Leonardo da Vinci, Michelangelo, Fra Carnevale, Gian Lorenzo Bernini, Sandro Botticelli, Tintoretto, Titian, Raphael, and Giotto, etc. Italian church architecture is equally spectacular and historically important to Western culture, notably St. Peter's Basilica in Rome, Cathedral of St. Mark's in Venice, and Brunelleschi's Florence Cathedral, which includes the "Gates of Paradise" doors at the Baptistery by Lorenzo Ghiberti. The status of the Catholic Church as the sole official religion in Italy ended in 1985, with the renegotiation of the Lateran Treaty. History Christianity arrived on the Italian peninsula in the first century, probably by unknown travelers, traders or soldiers. The Letter to the Romans of Paul the Apostle is addressed and attests to the presence of Roman Christians in the first century. Christians in Rome were also in touch with St. Peter and St. Paul the Apostle, both of whom went to Rome on mission and were eventually martyred there. One of the first Italian bishops and popes was Clement of Rome who wrote a letter to the Christian community in Corinth (1 Clement) around AD 96. Over its two thousand-year history, the Church of Italy grew in size and influence producing and harboring (sometimes before martyrdom) some of the greatest leaders and movers of Catholic Christianity including Priscilla and Aquila; Ignatius of Antioch, martyred in Rome; Polycarp, martyred in Rome and a disciple of John the Evangelist; Agnes, Roman martyr; Lawrence, martyr; Justin Martyr, teacher and martyr;