ISTANBUL, Turkey (AP) – Pope Benedict XVI looked toward Mecca.

He bowed his head. He prayed.

In that stunning moment in Istanbul’s most famous mosque Thursday, the pope stood before the entire Muslim world. It’s now their judgment on whether to accept the pontiff’s appeals for trust and reconciliation.

“This visit will help us find together the way of peace for the good of all humanity,” the pope said inside the 17th-century Blue Mosque after standing in silent prayer alongside the top Islamic cleric of Istanbul.

The message was designed to resonate loudly nearly three months after the Roman Catholic pontiff provoked worldwide fury for remarks on violence and the Prophet Muhammad. And the image is certain to be remembered as one of the historical moments of his papacy.

It was only the second papal visit in history to a Muslim place of worship. Benedict’s predecessor, John Paul II, made a brief stop in a mosque in Syria in 2001.

Benedict’s steps through a stone archway and into the mosque’s carpeted expanse capped a day of deep symbolism and lofty goals. Hours earlier, he stood beside the spiritual leader of the world’s Orthodox Christians and passionately encouraged steps to end the nearly 1,000-year divide between their churches.

The pope walked to the mosque after touring another majestic tribute to faith: the 1,500-year-old Haghia Sofia and its remarkable mix of Quranic calligraphy and Christian mosaics from its legacy as a marvel of early Christianity and then a coveted prize of Islam’s expansion.

At the mosque, the pope removed his shoes and put on white slippers. Then he walked beside Mustafa Cagrici, the head cleric of Istanbul. Facing the holy city of Mecca – in the tradition of Islamic worship – Cagrici said: “Now I’m going to pray.” Benedict, too, bowed his head and his lips moved as if reciting words.

Before the pope left, he turned to Cagrici and thanked him “for this moment of prayer.”

“A single swallow can’t bring spring,” Cagrici told the pope, who ends his first papal trip to a Muslim nation on Friday. “But many swallows will follow and we will enjoy a spring in this world.”

The pope received a painting showing the view of the Sea of Marmara from Istanbul and a glazed tile decorated with a dove. The mosque is officially known as the Sultan Ahmet Mosque, after the Ottoman sultan Ahmet I, who ordered its construction. But it’s widely called the Blue Mosque after its elaborate blue tiles.

The pope presented the imam with a mosaic showing four doves.

“Let us pray for brotherhood and for all humanity,” the pope said in Italian.

The Vatican spokesman, the Rev. Federico Lombardi, had said the mosque visit was added as a “sign of respect” to Muslims.

“A (Christian) believer can pray in any place, even a mosque,” he said, calling it an “intimate, personal prayer.”

The pope has offered wide-ranging messages of reconciliation to Muslims since arriving in Turkey on Tuesday, including appeals for greater understanding and support for Turkey’s steps to become the first Muslim nation in the European Union.

But Benedict also has set down his own demands.

The pope repeated calls for greater freedoms for religious minorities – including the tiny Christian community in Turkey – and denounced divisions between Christians as a “scandal.”

Benedict has made reaching out to the world’s more than 250 million Orthodox a centerpiece of his papacy and has set the difficult goal of “full unity” between the two ancient branches of Christianity, which split in the 11th century over disputes including the extent of papal authority.

“The divisions which exist among Christians are a scandal to the world,” the pope said after joining Ecumenical Patriarch Bartholomew I to mark the feast day of St. Andrew, who preached across Asia Minor and who tradition says ordained the first bishop of Constantinople, now called Istanbul.

The homage of the Orthodox feast day Liturgy also was highly significant to Roman Catholics. Andrew was the brother of St. Peter, who was martyred in Rome and is considered the first pope.

In a joint statement, the pope and patriarch stressed the need to “preserve Christian roots” in European culture while remaining “open to other religions and their cultural contributions.”

The comments could send conflicting signals to Turkey after the Vatican suggested there was room in the EU for its first Muslim member. They could also serve as a rallying point for groups opposed to bringing a predominantly Muslim country into the bloc.

The pope also recalled how the faith was shaped by the encounters of early Christians with the scientific and intellectual traditions of ancient Greece. It was the same theological backdrop – faith and reason – that was the basis for his explosive remarks in September in which he quoted a medieval Christian emperor who described Muhammad’s teachings as “evil and inhuman.”

The pope avoided any direct mention of Islam after praying with Bartholomew at the gilded St. George Church in Istanbul – the former Constantinople and capital of Christian Byzantium before falling to Muslim forces in 1453.

The echoes of the city’s turbulent history were among Benedict’s stops.

Haghia Sophia, once a spiritual center of Christianity, was converted to a mosque in the 15th century. The site became a museum following the sweeping secular reforms that formed modern Turkey in the 1920s.

The pope, wearing white robes, stopped often to gaze on Quranic passages carved in the ancient marble – in some places where crosses and the fish-shaped sign of early Christians were chiseled away. Above them were the frescoes and mosaics that couldn’t be touched by Muslims: figures such as Jesus and the Virgin Mary who are regarded as revered predecessors of Muhammad.

Security for the four-day pilgrimage has been stringent. But it grew even tighter as the pope moved about Istanbul.

Police blockades virtually sealed off parts of the city’s ancient heart. Snipers stood watch on the minarets added to Haghia Sophia following the Muslim conquest.

About 150 nationalists demonstrated against the pope’s visit to the site, gathering at a square about a half mile away and urging the government to open the museum to Muslim worship. Nationalists viewed the planned visit as a sign of Christian claims to the site and a challenge to Turkish sovereignty.

“Haghia Sophia is Turkish and will remain Turkish,” one protest sign read. Riot police surrounded the demonstrators to prevent them from advancing toward the site.

Of Turkey’s 70 million people, some 65,000 are Armenian Orthodox Christians, 20,000 are Roman Catholic and 3,500 are Protestant, mostly converts from Islam. Another 23,000 are Jewish.