Since we just talked about the apostles--let's talk about apostolic succession.
This is something we cover pretty briefly with the kids. We don't get into papal infallibility and all that (quickly: papal infallibility does not mean what you think it means), but we do talk about how a pope is elected and what the pope does.
Before we talk about that, though, we talk about basic hierarchy. From the bottom up:
- a pastor is in charge of a parish, which covers a territorial area. (a suburb, a city, part of a suburb or city, etc.)
- A bishop is in charge of a diocese--a larger territorial area.
- An archbishop is in charge of an archdiocese--an even larger area. Here in Ohio, we have the archdiocese of Cincinnati. An archdiocese doesn't have to be bigger in area, but in population. New York, Chicago, Philadelphia, Los Angeles--these are all archdioceses.
Archdioceses often have a cardinal as the bishop. (You have to be a priest before you can be a bishop, a bishop before you can be a cardinal) A third or fourth cousin of mine is Cardinal Wuerl, who's the bishop of Washington, D.C. He was made a cardinal by Benedict XVI. Bishops and cardinals are made by the pope.
All of the Cardinals make up the college of cardinals. Cardinals under the age of 80 elect the pope. (This is a rule created by Pope Paul VI, so it's a pretty new rule.). So, anyone who is a cardinal, under 80, can be elected pope.
(Fun Catholic fact: technically, any Catholic man can become pope. As in, my dad could be elected Pope. But then he'd have to be ordained and all that jazz. But technically, it could happen.)
So what does this have to do with apostolic succession? Well, we call it apostolic succession because the first pope was the apostle Peter.
From Matthew 16:
h When Jesus went into the region of Caesarea Philippi* he asked his disciples, “Who do people say that the Son of Man is?”14i They replied, “Some say John the Baptist,* others Elijah, still others Jeremiah or one of the prophets.”15He said to them, “But who do you say that I am?”16* j Simon Peter said in reply, “You are the Messiah, the Son of the living God.”17Jesus said to him in reply, “Blessed are you, Simon son of Jonah. For flesh and blood* has not revealed this to you, but my heavenly Father.18k And so I say to you, you are Peter, and upon this rock I will build my church,*and the gates of the netherworld shall not prevail against it.19l I will give you the keys to the kingdom of heaven.* Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven.”20* m Then he strictly ordered his disciples to tell no one that he was the Messiah.
This is the most common Scripture cited for Peter's primacy and the establishment of the Papacy. Every Pope since then has followed into the "Petrine office" (Petrine--Peter).
Now, there have been some pretty awful popes. There have also been many saintly ones. The office doesn't automatically make you holy. But the Pope is in charge, spiritually, of all the 1 billion+ Catholics in the world. Pope Francis is Pope Number 266. He's also the first pope named Francis--and you don't call him "Pope Francis I." We can't call him that until there's been a Francis II.
The tradition of regnal names began with Pope John II, in 533. His given name was Mercurius, after the Roman god Mercury, and he didn't think that was an appropriate name for a Christian pope! So every pope since then has had the option of a regnal name. John Paul II's baptismal name was Karol; Benedict XVI's was Joseph, and Francis' was Jorge.
The pope's role has changed over the centuries, but he has always been the spiritual leader of the world's Catholics.