Following the death of Pope John Paul II, Cardinal Joseph Ratzinger became Pope Benedict XVI in April 2005. He was elected after four ballots of the papal conclave.
The late Cardinal Cormac Murphy-O'Connor took part and told Rebecca Kesby the story of how the new leader of the Catholic Church was chosen by 115 cardinals.
This programme was first broadcast in 2013.
(Photo: Pope Benedict XVI. Credit: Getty Images)