Pope Benedict has returned to Rome at the end of his first visit to a predominantly Muslim country having apparently successfully defused criticism that he views the Islamic faith as "violent".
The BBC's Rome correspondent, David Willey, who followed the Pope's journey to Turkey, reflects on an historic week.
The Pope followed up on promises with some striking gestures
The 79-year-old Pope scored a considerable diplomatic success.
Popes usually go down in history more for what they do than for what they say.
The reign of the 16th-Century Pope Sixtus V is still remembered for his architectural transformations of the city of Rome.
Pope John XXIII is remembered for having called the Second Vatican Council. And Pope John Paul II is remembered as the most travelled Pope in history.
In Istanbul, we have, I believe, witnessed some defining moments of the papacy of Benedict XVI.
He reached out to Muslims by praying facing towards Mecca in a famous mosque.
And he reached out to Orthodox Christians, seeking to heal a rift that has lasted more than 1,000 years by holding joint services and giving a joint blessing to their faithful by the side of Patriarch Bartholomew, their spiritual leader, on the holiest day in their church calendar.
Pope Benedict followed up on promises he had previously made at the Vatican with some very striking and eloquent gestures.
The Pope won the praise of Turkey's former religious affairs director Mehmet Nuri Yilmaz for facing Mecca when he prayed in silence inside Istanbul's Blue Mosque.
ISTANBUL'S FAMOUS SITES
Blue Mosque: built in 1616 on Sultan Ahmet I's orders
John Paul II is the only other Pope to have entered a mosque
Hagia Sophia: built in 6th century as a church
converted to a mosque in 1453, a museum since 1935
The visit to the mosque, an extra stop inserted in the Pope's programme only at the last minute, appears to have gone down extremely well with his hosts.
It was a bold gesture, considering that this was only the second time in the history of the papacy that a pope from Rome has entered a Muslim place of worship.
I was also present when the late Pope John Paul II broke with precedent by entering the great Umayyad mosque of Damascus during his visit to Syria five years ago.
But that occasion was more a courtesy visit than an opportunity for deep prayer.
Benedict closed his eyes and moved his lips in prayer for what seemed like two very long minutes after being shown around this famous gem of 17th-Century Ottoman architecture.
It is known as the Blue Mosque because of the intricately patterned and coloured tiles which decorate part of the interior of the building.
The moment was "even more meaningful than an apology" for the Pope's much criticised remarks about the Prophet Muhammad in September, said the Mufti of Istanbul, Mustafa Cagrici, the Pope's guide during the visit.
The religious and historical symbolism of the Pope's journey to Istanbul has been striking.
Turkey's former capital city straddles the narrow waterway dividing Europe from Asia.
The Pope's Blue Mosque prayer impressed Turkish observers
One of its dominant monuments is the broad-domed former Christian church of Hagia Sophia, built by the Roman Emperor Justinian 1,500 years ago.
For centuries this was the largest church in the world. After the fall of Constantinople in 1453, Hagia Sophia became a mosque; now it is a museum.
The Pope therefore had to respect the secular nature of this former holy place, which still contains a mosaic more than 1,000 years old depicting a Byzantine Emperor prostrating himself before a seated figure of Christ.
Yet a prayer here would have been considered out of place.
It would have offended his hosts, the government of the secular Turkish state.
Benedict respected protocol. But 10 minutes later, under the glare of television lights, he was praying at the side of an imam inside the Blue Mosque, only 500 metres (yards) away from Hagia Sophia.
Whether Pope Benedict's visit has brought Turkey any nearer to full membership of the EU remains a moot point.
Mr Erdogan said the Pope had given his support to Turkey's EU bid
Certainly Prime Minister Recep Tayyip Erdogan made the most of a private remark to him by the Pope, when the pontiff stepped off his plane in Ankara, to the effect that he welcomed the negotiations now going on in Brussels.
This was interpreted by Mr Erdogan as full papal support for Turkey, and duly reported as such in the local press.
But a Vatican official later put a perhaps more realistic spin on the Pope's remarks.
He pointed out that the Vatican - which incidentally is not a member of the EU - normally takes no stand on purely political issues, while supporting the basic ideals and goals of European unity because of the continent's common Christian roots and traditions.