Intense preparations are being carried out as the Pope prepares to meet a revered Shia cleric in Iraq's holiest city.
Francis and Grand Ayatollah Ali al-Sistani will seek to make history in Najaf with a message of coexistence in an area plagued by bitter divisions.
Al-Sistani is a pre-eminent figure in Shia Islam, whose opinion holds powerful sway on the Iraqi streets and beyond.
Their encounter will resonate across Iraq, even crossing borders into mainly-Shia Iran.
The head of the Catholic church and the Grand Ayatollah are scheduled to meet on Saturday for around 40 minutes, spending part of the time alone except for interpreters, in the Shia cleric's modest home in the city of Najaf.
Every detail is being scrutinised ahead of time in painstaking, behind-the-scenes preparations that touched on everything from shoes to seating arrangements.
The geopolitical undertones weigh heavy on the meeting, along with twin threats from the coronavirus pandemic and ongoing tensions involving Iranian-backed rogue groups.
For Iraq's dwindling Christian minority, a show of solidarity from al-Sistani could help secure their place in Iraq after years of displacement - and, they hope, ease intimidation from Shia militiamen against their community.
Iraqi officials in government, too, see the meeting's symbolic power - as does Tehran.
The 90-year-old al-Sistani has been a consistent counterweight to Iran's influence. With the meeting, Francis is implicitly recognising him as the chief interlocutor of Shia Islam over his rival, Iranian Supreme Leader Ali Khamenei.
News of the meeting heightened long-standing rivalries between the Shia seminaries of Najaf and Iran's city of Qom, which stands at the centre of the Shia world.
One official involved in the planning said: "It will be a private visit without precedent in history, and it will not have an equal to any previous visits."
For the Vatican, it is a meeting decades in the making, and one that eluded Francis' predecessors.
"Najaf did not make it easy," said one Christian religious official close to the planning from the Vatican side.
Al-Sistani rarely weighs in on governance matters, but when he has, it has shifted the course of Iraq's modern history.
An edict from him provided many Iraqis reason to participate in the January 2005 elections, the first after the 2003 US-led invasion.
His 2014 fatwa calling on able-bodied men to fight the so-called Islamic State group massively swelled the ranks of Shia militias.
In 2019, as anti-government demonstrations gripped the country, his sermon led to the resignation of then-prime minister Adil Abdul-Mahdi.
The Vatican's hope is that Francis will sign a document with al-Sistani pledging human fraternity, just as he did with Sunni Islam's influential grand imam of al-Azhar, Ahmed el-Tayeb, based in Egypt.
The signature is among many elements the two sides negotiated over extensively. In the end, Shia religious officials in Najaf told the AP a signing was not on the agenda, and al-Sistani will issue a verbal statement instead.
Each minute of Saturday's meeting is likely to unfold as meticulously as a scripted stage play.
The 84-year-old pontiff's convoy will pull up along Najaf's busy column-lined Rasool Street, which culminates at the Imam Ali Shrine, one of the most revered sites in the world for Shias.
To the side is an alleyway too narrow for cars. Here, Francis will walk the 30 yards to al-Sistani's modest home, which the cleric has rented for decades. Waiting to greet him at the entrance will be al-Sistani's influential son, Mohammed Ridha.
Inside, and some steps to the right, the pontiff will come face-to-face with the ayatollah. Each will make a simple gesture of mutual respect.
Francis will remove his shoes before entering al-Sistani's room.
Al-Sistani, who normally remains seated for visitors, will stand to greet Francis at the door and walk him to an L-shaped blue sofa, inviting him to take a seat.
"This has not taken place by his Eminence with any guest before," said a Najaf religious official.
He will stand despite his fragile health, said the religious officials. Since fracturing his thigh last year, the cleric has largely remained indoors. Francis suffers from sciatica.
The Pope will then be offered tea.
"His Eminence will provide His Holiness a message of peace and love for all humanity," said the official, before gifts are exchanged.
Until now, papal plans to visit Iraq have ended in failure.
The late Pope John Paul II was unable to go in 2000, when negotiations broke down with the government of then-Iraqi leader Saddam Hussein.
Politics and rivalries aside, many people across Iraq will have something to gain from the short encounter.
"I see the pope's visit to Najaf as the culmination of a global movement in the Islamic-Christian tradition to promote security and peace in our country," Iraq's culture minister Hassan Nadhem told the press recently, "as we are still tinged with tendencies toward violence and intolerance."