Margherita Guarducci, acclaimed scholar of ancient literature, extending her research to various disciplines, such as philology, ancient history, archaeology and epigraphy, demonstrates how they contribute toward clarifying and resolving a centuries-old problem: the primacy of the Church of Rome over the other Christian Churches. The resulting picture spans over two millennia of history, illuminated by several "primacies" of Christianity, gathered and evaluated together for the first time; ownership of the oldest Christian basilica, the oldest portrait of Christ, the oldest icon of Mary, and, most importantly, the oldest relic of St. Peter in the Vatican Basilica. Guarducci gives evidence of certain concatenations of events which tend to confirm the primacy of the Church of Rome, the ancient universality of which survives to this day in the spiritual primacy of the Roman "Catholic"--that is, Universal--Church. And this survival is guaranteed down through the centuries by extraordinary presence in the Vatican of the authentic earthly remains of the Apostle whom Christ selected as His vicar on earth. Illustrated.