Have there been 265 popes? Journalists refer to Benedict XVI as the 265th pope, but numbering the popes is a tricky matter. The Vatican yearbook, the Annuario Pontificio, counsels against numbering the popes, because of some ambiguity about who was the legitimate pope at various times in church history. For example: It is impossible, on the basis of the facts we have, to state with certainty which of two 10th-century popes, Leo VIII or Benedict V, was legitimate. Also, there is great confusion regarding the 11th-century pope Benedict IX, who is understood to have been pope three times; we could call him the Grover Cleveland of the papacy.

I have an ongoing hobby of studying the history of the papacy. For convenience I do as journalists do, and assign ordinal numbers to the popes, with Benedict XVI as number 265.

What is the significance of the papacy to non-Catholic Christians and to people in general? In Christianity, there is reverence for what can be called the "Petrine office" of the pope. In other words, the office of the successor of St. Peter is understood to be a focus of unity for all Christians.

Of course, there has been controversy about how the mission of the Petrine office is carried out. There are many Christians who do not necessarily hold to the idea of one person as the wielder of supreme authority. Eastern Orthodoxy looks upon the "patriarchate" of Rome as one of five ancient patriarchates called the "Pentarchy" (Rome, Constantinople, Alexandria, Antioch, Jerusalem), holding that, in theory, Christianity could be governed by a consensus among several patriarchs. Blessed John Paul II, in his 1995 encyclical letter Ut Unum Sint (That They May Be One), called for "a patient and fraternal dialogue" on the meaning of the Petrine office within a Christianity in search of greater unity.

We remember with gratitude the invitation of John Paul II to people of non-Christian religions to meet with Christians in prayer for world peace. Three such gatherings took place at the initiative of John Paul II: in 1986, 1993, and 2002. The response of numerous religious groups on these occasions demonstrated that the head of the Catholic Church is in fact influential in bringing together people who, out of various religious traditions, seek common paths toward establishing a state of peace worthy of humanity.

If you'd like to explore the history of the papacy, I recommend J.N.D. Kelly, The Oxford Dictionary of Popes (1986). This book gives capsule biographies of popes through John Paul II, along with similar biographies of 37 antipopes (false claimants to the papacy) and three other men whose situations are so puzzling as to be unclassifiable.

As we witness history being made, we keep in mind the origins of the Christian people of God in the gathering of scared and dispirited people in Jerusalem who had lived through the death of Jesus and were amazed at becoming witnesses to his resurrection. This complex thing we call "the church" carries out the same mission today: to proclaim that God has accomplished the redemption of humanity.