The Vatican said the Pope wanted to return US hospitality
US President George W Bush has been afforded a special audience with Pope Benedict XVI, on his final official visit to meet the pontiff.
The president spoke with the Pope in the medieval St John's Tower, a venue reserved for illustrious guests, before taking a stroll in the Vatican Gardens.
Mr Bush was heard to say "what an honour" as the Pope showed him round.
The Vatican says Mr Bush's treatment is in return for the hospitality shown the Pope on a recent visit to the US.
But the BBC's Christian Fraser in Rome says there is more to it than that.
Notwithstanding their differences on Iraq and the Middle East, this is an evangelical president who has always defended the Christian message, he says.
Mr Bush's conservative line on abortion and stem cell research are strongly supported by the Vatican, our correspondent points out.
And the Holy See has welcomed the Bush administration's support for development in Africa. Analysts say that for Republicans watching in the United States, this relationship with the Vatican is important.
Blue-collar Catholic voters will be a key group in the swing states come November's US presidential election.
Pope Benedict XVI greets President Bush on his arrival in Rome
Mr Bush is travelling round European capitals on a farewell tour, before he leaves office early next year.
On Thursday he was greeted by anti-war protests as he met Italian Prime Minister Silvio Berlusconi in Rome.
Iran's disputed nuclear programme is expected to stay on the agenda during the tour, and analysts say the pontiff could play a role.
Unlike the Americans, the Vatican has opened diplomatic relations with Tehran, which has one of the biggest embassies to the Holy See.
The pontiff's message last year to the Supreme Leader, Ayatollah Ali Khamenei, was credited with helping secure the release of a group of British sailors seized in the Gulf.
After Rome, Mr Bush flew on to Paris, where he was to meet French President Nicolas Sarkozy.
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