US President Barack Obama met Pope Benedict XVI for the first time yesterday, thanking him for a "great honour" as they went into private talks in the pontiff's personal library at the Vatican.
Both men were all smiles as they warmly shook hands, Mr Obama in a black suit and tie and Pope Benedict wearing a red chasuble over a lace surplice covering his white cassock.
"It's a great honour, thank you very much," Mr Obama said.
The US leader, who met first with Vatican Secretary of State Tercisio Bertone, was expected to discuss both areas of agreement such as foreign policy and those that divide them, notably abortion.
Mr Obama "recognises that this is much more than your typical state visit," his aide Denis McDonough said in nearby L'Aquila, central Italy, where a three-day Group of Eight summit, which Mr Obama attended, was winding up. Photographers at the Vatican overheard Mr Obama telling the Pope that the summit of powerful nations had been "very productive and concrete," adding that world leaders had agreed a food security programme worth $20 billion.
At the private audience, "there are issues on which they'll agree, issues on which they'll disagree, and issues on which they'll agree to continue to work on going forward," Mr McDonough said.
After taking office in January, Mr Obama ended his predecessor George W. Bush's restrictions on government funding for embryonic stem cell research and for family planning groups that carry out or facilitate abortions overseas.
White House spokesman Robert Gibbs said aboard Air Force One en route to the G8 summit that he expected the discussion to be "frank."
"There's a lot that they agree on that they'll get a chance to discuss," he said.
Vatican expert John Allen said the two share a long list of common views: "There's foreign policy, Islam, the environment, the poor, health care, and on and on," he said.
"We know the Pope has been keenly aware of the President's outreach to the Muslim world (and) the Pope shares the President's view on reducing the number of nuclear weapons," Mr Gibbs said.
Mr Obama told the Italian bishops' mouthpiece L'Avvenire that he hoped to find much common ground with the Pope "from peace in the Middle East to the fight against poverty, from climate change to immigration, all these areas where the Pope has shown extraordinary leadership."
The US President and the 82-year-old Pope, head of the world's 1.1 billion Catholics, notably see eye to eye on policy in the Middle East.
Mr Obama has made relaunching the peace process there a top priority, pledging a new beginning for Islam and the United States in a landmark speech to the world's Muslims delivered in Cairo last month.
The Vatican called this a "significant" step toward better ties.
Vatican daily L'Osservatore Romano said Mr Obama, a committed Christian, had gone "beyond political formulas, invoking concrete common interests in the name of a shared humanity."
Mr Allen said: "From the beginning it's been clear that the Vatican has taken a more balanced and positive view (of Mr Obama) regardless of the cultural divide in the United States."