Pope Benedict visited Istanbul's Blue Mosque today and appeared to pray alongside a leading Islamic cleric.
The visit that made him only the second Roman Catholic Pontiff to enter a mosque. The dramatic gesture was seen as yet another attempt by the Pope at reconciliation after he infuriated much of the Muslim world with comments implying Islam was a violent and irrational faith.
The Pope took off his shoes and donned what white cloth slippers when he entered the mosque and was told about its history and architecture by Istanbul's Grand Mufti Mustafa Cagrici.
Towards the end of the visit, which lasted about 20 minutes, the two stood side by side for about a minute. The Pope kept his arms crossed at his waist. His lips could be seen moving silently.
The Muslim cleric prayed aloud and touched his faced in the traditional Islamic gesture at the end of prayer. The Pope nodded and the two exchanged gifts before Benedict left.
Asked if the Pope had prayed, Vatican spokesman Father Federico Lombardi would only say: "The Pope paused in meditation and certainly addressed his thoughts towards God".
Benedict's predecessor Pope John Paul II made the first papal visit to a mosque during a trip to Damascus in 2001.
"This visit will help us find the means and the ways of peace for the good of all humanity," the Pope told the Mufti as the visit was drawing to a close.
The Blue Mosque, known officially as the Sultan Ahmet mosque, opened in 1616 and is the most famous in Turkey. It got its popular name from the fine blue Iznik tiles in the main prayer room.
It stands in Sultan Ahmet Square in the old centre of Istanbul, opposite the Aya Sofya museum which was once the Christian church Hagia Sophia.
The Pope visited the mosque after a short tour of Aya Sofya.
His visit was a late addition to his schedule meant as a gesture of respect for Islam after he angered Muslims with apparently critical comments in a speech in September. The German-born Pope has already defused much of the tension linked to his visit, his first to a mostly Muslim country, by supporting Ankara's bid to join the European Union and praising Islam as a religion of peace.
Earlier, Benedict and the spiritual leader of Orthodox Christians prayed together and signed a common declaration that appeared to jointly support Turkish membership if it protected religious liberties.
In the declaration, Benedict and Patriarch Bartholomew rejected the concept of killing in God's name, denounced terrorism and re-committed their Churches to the quest for unity and condemned violence in the Holy Land.
The EU wants Turkey to ensure full religious freedom for its non-Muslim minorities before allowing it join.
Earlier, dozens of nationalists protested against Pope Benedict's visit to and urged him to not to visit the Blue mosque.
Police arrested one man trying to make a speech at a police barricade next to Aya Sofya, now a museum.
After a short stand-off with several hundred riot police at a nearby square, the Grand Unity Party (BBP) protesters peacefully dispersed.
"Next they will try to make Istanbul Constantinople again. We will not allow that," Bayram Karacan, head of the BBP's Istanbul wing, told the 100-strong crowd after Muslim prayers.