Ruth Sherlock

He walked in white socks across the red carpeted floor as he was given a tour by the mosque's Imam and the Mufti of Istanbul.

The Imam told reporters he invited Leo to pray

But the Pope declined.

The Vatican said in a statement afterwards that, quote, the Pope experienced his visit to the mosque in silence, in a spirit of contemplation and listening, with deep respect for the place and the faith of those who gather there in prayer.

Ruth Sherlock, NPR News, Istanbul, Turkey.

Pope Leo and Patriarch Bartholomew, the spiritual leader of the world's Orthodox Christians...

stood side by side during speeches and prayer at archaeological ruins on the shore of Lake Iznik.

It was here that in the year 325, bishops gathered from across the Roman Empire to heal divisions within the church and establish the statement of faith that Christians still recite today.

Speaking at this historical site, Leo called on the world to reject the use of religion for justifying war, violence or any form of fundamentalism.

Instead, he said, choose dialogue and cooperation.

Ruth Sherlock, NPR News, is Nick Turkey.

Pope Leo will visit the archaeological ruins in Turkey's Iznik that are believed to be the site where, in the year 325,

bishops gathered from around the Roman Empire and settled upon the Nicene Creed.

The statement of Christian faith that commits to believing in one God is still spoken in churches today.

It's a unifying document for a faith that has seen schisms throughout the ages

into many different denominations.

Pope Leo will pray at the site of the Nicene Creed alongside Patriarch Bartholomew, the spiritual leader of the world's Orthodox Christians.

Pope Leo hopes this moment will be a call for unity.

Ruth Sherlock, NPR News, Turkey.

In his speech, made alongside President Erdogan in a large library in Ankara, Pope Leo said Turkey's grand Ottoman past is both a gift and a responsibility.