Because he has been one of the most powerful men in the Vatican for over 20 years.

Because he is widely acknowledged as the church's leading theologian.

Because he served Pope John Paul II (he is to that pontiff's right) since 1981 as head of the influential Congregation for the Doctrine of the Faith.

Because he went into the conclave of cardinals with the most buzz among a dozen leading papal contenders after his stirring homily at John Paul II's funeral.

Because some cardinals felt though he never spoke of it, Pope John Paul II had in mind Cardinal Ratzinger as his successor.

Because he is 78, and his papacy will not be as long as the 26 years Pope John Paul II led.

Photograph: Patrick Hertzog/AFP/Getty Images

Also read: All roads lead to Rome