A respected observer of Vatican affairs talks about today's big announcement.

In an unexpected announcement, the Vatican has announced that Pope Benedict XVI will resign on February 28 due to health reasons. The announcement is seen by many as a break with tradition. I spoke to Gerard O'Connell, a Rome-based author and journalist specializing in Vatican affairs.

What do you make of the speculation surrounding this announcement and what will Pope Benedict's resignation mean for his successors?

The bar is very high for popes who will follow because he is saying that if a man doesn't have the physical or mental strength to do the job, that it is appropriate that he resigns. It has always been a possibility with Benedict XVI that he would resign because he has spoken about the possibility of a pope resigning many times.

Pope Benedict's resignation is unprecedented in the modern era. What will be the impact of his resignation?

His decision is a [historic] decision. No pope in modern times has resigned. Everyone has died in office. But he is a pope whose mind is very clear, still physically able, but he came to a very conscious decision. He weighed the task of the job that he has and he weighed his own mental, physical resources to do that task and he came to a very rational conclusion that "I am no longer up to this task."

What will Pope Benedict be known for? What has been his legacy?

Well he stands out as a teacher of the Christian faith. He is the only pope to have ever written the biography of Jesus and he really has excelled as a professor by profession, before he became a bishop, before he became a cardinal, before he became a pope. And he continued being a scholar and teacher of the faith. And also he will be remembered as a man of virtue and kindness.

While there are no official candidates, there are several names being mentioned. Are there any front-runners at this point?

Well it is very difficult to say where the next pope will come from. I think we have some Italian candidate, [and] there is one from North America. There could be one or two from South America. It is very difficult to predict right now.

What has been the reaction to the pope's resignation?

I mean the whole Church has been surprised. I think maybe one or two people knew. Presumably he told one or two people but last year we had a year of leaks of all kinds from the Vatican. This year, this has been the best kept secret in this pontificate.