The trip comes as Iraq, ravaged by decades of conflict, faces a second deadly wave of coronavirus infections and renewed violence.

Persecution has already slashed the country's Christian community -- one of the world's oldest -- from 1.5 million in 2003 to just 400,000 today.

The 84-year-old pontiff plans to voice solidarity with them and the rest of Iraq's 40 million people during an intense week of visits nationwide.

From central Baghdad to the Shiite shrine city of Najaf, welcome banners featuring his image and Arabic title "Baba al-Vatican" already dot the streets.

From Ur, the birthplace of the Prophet Abraham in the southern desert, to ravaged Christian towns in the north, roads are being paved and churches rehabilitated in remote areas that have never seen such a high-profile visitor.

"The Pope's message is that the Church stands beside those who suffer," said Najeeb Michaeel, Chaldean Catholic Archbishop of the northen city of Mosul.

"He will have powerful words for Iraq, where crimes against humanity have been committed."

- Ancient roots -

Iraq's Christian community is one of the oldest and most diverse in the world, with Chaldeans and other Catholics making up around half, along with Armenian Orthodox, Protestants and others.

By 2003, when the US-led invasion toppled then-dictator Saddam Hussein, Christians made up around six percent of Iraq's 25 million people.

But even as sectarian violence pushed members of the minority to flee, the national population surged, further diluting Christians to just one percent according to William Warda, co-founder of the Hammurabi Human Rights Organisation.

Most were concentrated in the northern province of Nineveh, where many still speak a dialect of Aramaic, the language of Jesus Christ.

In 2014, Islamic State group jihadists seized control of Nineveh, rampaging through Christian towns and telling residents: convert or die.

At the time, Pope Francis endorsed military action against IS and considered visiting northern Iraq in solidarity with Christians there.

That trip never materialised, but Francis has kept a close eye on Iraq, condemning the killing of unarmed protesters during mass anti-government rallies from 2019.

- A long time coming -

Pope John Paul II had planned to visit Iraq in 2000 but Saddam Hussein abruptly cancelled the trip. His successor Benedict XVI never made moves towards Baghdad.

Soon after Francis was elected pope in 2013, he was urged to visit Iraq by Father Louis Sako -- later appointed as Cardinal and the head of the Chaldean Catholic Church and now a key organiser of the visit.

In 2019, President Barham Saleh extended an official invitation, hoping to help Iraq "heal" after years of violence.

But as the Covid-19 pandemic ravaged Italy, the Pope cancelled all foreign trips from June 2020.

His venture to Iraq, his first post-pandemic trip, has a packed itinerary.

He lands on Friday morning in Baghdad with a security team and a cohort of 75 journalists who, like the Pope, have already been vaccinated.

Over the next three days, he will host masses in Baghdad, Kurdish regional capital Arbil and Ur.

Vatican teams have made several trips to Iraq to flesh out the details, but it is clear that this will be unlike any other papal visit.

Swamped by some 4,000 new coronavirus cases per day, Iraq has imposed overnight curfews and full weekend lockdowns that will be extended to cover the entire visit.

Social distancing will be enforced at all of the church services and those hoping to attend had to register several weeks in advance.

- 'A huge impact' -

Pope Francis is an outspoken proponent of interfaith efforts and has visited several Muslim-majority countries including Bangladesh, Turkey, Morocco and the United Arab Emirates.

In Abu Dhabi in 2019, he met Sheikh Ahmed al-Tayeb, the imam of the Al-Azhar mosque in Cairo, a key authority for Sunnis worldwide.

They signed a document encouraging Christian-Muslim dialogue.

Francis hopes his Iraq trip could open a similar door to Shiite Muslims, who number roughly 200 million worldwide but are the majority in Iraq. As part of that effort, he will meet the top cleric for many Shiites, Grand Ayatollah Ali Sistani, at his humble home in Najaf.

Sako told AFP in January that the Pope hoped Sistani would endorse the same "Abu Dhabi" treatise signed by Tayeb, but clerical sources in Najaf have denied this.

Still, the encounter will be a key moment in an emblematic trip.

"It's a historic visit -- we're talking about the head of a religious sect that is followed by 20 percent of the world's population," Najaf governor Luay al-Yasserit old AFP.

"His visit means a lot. His visit to His Holiness, the top cleric, Grand Ayatollah Ali Sistani, will have a huge impact."