The former Cuban president Fidel Castro asked the Pope a question he may not have expected on the final day of his three-day visit to Cuba: "What does a pope do?"
The two men, one the leader of the worldwide Catholic Church and the other the founder of a self-declared atheist nation, spoke for about thirty minutes at the Vatican embassy in Havana.
Vatican spokesman Father Federico Lombardi said Benedict, 84, and Castro, 85, had an "exchange of ideas" in a "very cordial" atmosphere, and also joked about their age.
Castro led the communist revolution in Cuba in 1959 and ruled the Caribbean nation for 49 years, handing power to his his son Raul in 2008 when his health deteriorated.
He arrived at the meeting with the pontiff in a green Mercedes SUV surrounded by armed guards and a convoy of black Mercedes cars.
Wearing a Reebok tracksuit and scarf, and supported by two assistants, Castro told the pontiff that he now spends much of his time reading and reflecting on the state of the world.
He also asked the Pope for a book to help him understand changes in Church liturgy. Lombardi said the Pope hadn't yet decided which book to send him.
In answer to the question posed, the Pope spoke about his ministry, his foreign trips and his service to the Church. He said he was happy to be in Cuba and with the welcome he received.
Whilst relations between the Catholic Church and communist country have warmed in recent years, the Pope hopes that the Church will be granted greater powers in Cuba. Before his visit, he asked the Government to consider making Good Friday a national holiday.