Pope Francis began the second day of his historic Iraq visit on Saturday with an extraordinary meeting with Ayatollah Ali Al Sistani, the top authority for the country's Shiite Muslims.
The 84-year-old pontiff is defying a second wave of coronavirus cases and renewed security fears to make a long-awaited trip to Iraq, aiming to comfort the country's ancient Christian community, while also deepening his dialogue with other religions.
Having spoken to the faithful in Baghdad on Friday, Francis travelled to the shrine city of Najaf, in central Iraq, early on Saturday, to see the 90-year-old Shiite leader.
The two met in Mr Al Sistani's home in one of Najaf's tiny alleyways, with no press allowed, as the ayatollah is almost never seen in public.
The visit is one of the highlights of the Pope's four-day trip to Iraq, where Mr Al Sistani has played a key role in lowering tensions in recent decades.
It took months of negotiations between Najaf and the Vatican to secure the one-on-one meeting.
"We feel proud of what this visit represents and we thank those who made it possible," said Mohamed Ali Bahr Al Ulum, a senior cleric in Najaf.
On his arrival, the Pope was greeted by posters featuring a famous saying by Ali, the fourth caliph and the Prophet Mohammed's relative, who is buried in Najaf.
"People are of two kinds, either your brothers in faith or your equals in humanity," read the banners.
Pope Francis, a strong proponent of interfaith efforts, has met top Sunni clerics in several Muslim-majority countries, including the UAE, Bangladesh, Turkey and Morocco.
Mr Al Sistani, meanwhile, is followed by most of the world's 200 million Shiites – a minority among Muslims but the majority in Iraq – and is a national figure for Iraqis.
"Ali Sistani is a religious leader with a high moral authority," said Cardinal Miguel Angel Ayuso Guixot, head of the pontifical council for interreligious dialogue and a specialist in Islamic studies.
Mr Al Sistani began his religious studies at the age of five, ascending through the ranks of Shiite clergy to grand ayatollah in the 1990s.
While Saddam Hussein was in power, he languished under house arrest for years, but emerged after the US-led invasion that toppled the repressive regime to play an unprecedented public role.
In 2019, he stood with Iraqi protesters demanding better public services and shunning external interference in Iraq's domestic affairs.
On Friday in Baghdad, Pope Francis made a similar plea.
"May partisan interests cease, those outside interests who don't take into account the local population," the Pope said.
Mr Al Sistani has had a complicated relationship with his birthplace Iran, where the other main seat of Shiite religious authority lies: Qom.
While Najaf affirms the separation of religion and politics, Qom believes the top cleric – currently Iran's supreme leader Ayatollah Ali Khamenei – should also govern.
Iraqi clerics and Christian leaders said the visit could strengthen Najaf's standing compared to Qom.
"The Najaf school has great prestige and is more secular than the more religious Qom school," Cardinal Ayuso said.
"Najaf places more weight on social affairs."
In Abu Dhabi in 2019, the Pope met Sheikh Ahmed Al Tayeb, the imam of the Al Azhar mosque in Cairo and a key authority for Sunni Muslims.
They signed the Document on Human Fraternity encouraging Christian-Muslim dialogue. Catholic clerics hoped Mr Al Sistani would also endorse the text, but clerical sources in Najaf said it was unlikely.
While the Pope has been vaccinated and encouraged others to get the jab, Mr Al Sistani's office has not announced his vaccination.
Iraq is currently gripped by a resurgence of coronavirus cases, recording more than 5,000 infections and more than two dozen deaths daily.
After his visit to the ayatollah, Pope Francis will head to the desert site of the ancient city of Ur, believed to be the birthplace of the Prophet Abraham, where he will host an interfaith service attended by many of Iraq's other religious minorities.