There is no interim pope. However, upon the death or resignation of a pope the camarlengo acts as a temporary administrator until the new pope is elected. He has no power to make major decisions and primarily arranges the papal funeral as well as preparations for the upcoming conclave. In the case of Pope Benedict XVI that was Cardinal Tarcisio Pietro Evasio Bertone.
The camarlengo assumes leadership in the absence of a pope. He has no power to make any changes to the Church and his primary responsibilities would be to arrange for the funeral of the previous pope and set up the conclave to elect a new pope.
The cardinals frequently select one of the older and more experienced members of the college to be pope. However, when Pope John Paul II was elected he was only 58 years old. Sometimes, if they are having problems choosing a pope, they might compromise and choose an 'interim' pope, one of their oldest members who will probably serve only a short time hoping that one or two popular leaders emerge during the interim pope's reign.
.Catholic AnswerPope John XXIII preceded Pope Paul VI. Pope John XXIII was elected when Pope Pius XII died. They really didn't think he was going to be Pope very long, or do anything much. He called and opened the Second Vatican Council. So much for "interim" popes who don't accomplish much, the Lord works in mysterious ways. See the Vatican article on Pope John XXIII, he was a very nice man, I remember reading his diary, he was also a very holy man.
Pope Paul VI was elected pope after the death of Pope John XXIII.
John Paul II
There is no pope named Pope XXIII. If you are referring to Pope John XXIII, he became pope in 1958.
Pope Francis is the reigning pope in 2013.
The current pope is Pope Benedict XVI.
Pope Pius III was the predecessor of Pope Julius II.
Pope Benedict followed Pope John Paul II as pope.
It was Pius XII. He was pope from Mar. 2, 1939 to his death on Oct. 9, 1958.
Pope Pius I was the 10th pope.