A decade after being forced to flee Iraq during the rise of Daesh, the former archbishop of Mosul is returning to become head of the country’s Chaldean Catholic Church, bringing a message of faith tested by suffering.

Speaking ahead of his installation in Baghdad on May 29, Patriarch-elect Amel Shamon Nona told the Catholic charity Aid to the Church in Need that his experience of persecution had shaped his leadership. He was elected Patriarch of Baghdad of the Chaldeans by the Synod of Bishops of the Patriarchal Church of Baghdad of the Chaldeans on April 12, and has taken the name Paul III.

He said: “It was a very difficult but defining time. Being a bishop in a city in constant danger, where every week or month someone was killed, left a deep mark on me.

“But it also taught me that the faith of our people is their true anchor. Despite everything, they kept their hope alive.”

Patriarch-elect Nona added: “To suffer for being a faithful believer certainly deepens your way of looking at life…

“That is the hope I carry into this new mission. They suffered immensely, yet they have this deep, unshakable belief.”

The new head of the Chaldean Catholic Church has chosen as his motto “Do not be afraid, just believe” – taken from chapter five of St Mark’s Gospel – describing fear as “the biggest challenge in the world today”.

He succeeds Cardinal Louis Raphaël Sako, whose resignation was announced in March. Archbishop Nona had led the Chaldean Eparchy of St Thomas the Apostle in Sydney before his election as patriarch.

He takes up the role at a time of continuing uncertainty for Christians across the Middle East, where conflict, instability and emigration have reduced historic communities.

The patriarch-elect called on the international community to help end conflict in the region, saying recurring wars were undermining stability.

He said: “We cannot accept that every year there is a new war. The people of the Middle East want to live in serenity… we need the world to stop turning our land into a constant battlefield.”

One key challenge for the new patriarch will be addressing the growing divide between those remaining in the region and the diaspora overseas.

Patriarch-elect Nona, who has spent the past decade shepherding the Chaldean Church in Australia, said his priority was to “build a bridge” between the two.

He said: “The original home of our Church is in Iraq, but today the majority of our people live abroad,” adding that younger generations were searching for identity and faith.

Addressing young people considering emigration, he said: “Wherever you are, you have a mission… Practise your faith, preach it through your actions, and live as the Lord wants.”

Patriarch-elect Nona thanked Aid to the Church in Need for its support, particularly during the period in which Daesh had seized control of Iraq’s Nineveh Plains.

He said: “ACN has worked very well [with us] in the past, and I believe we will continue that vital work together to ensure that our people have a future and above all, that they have hope.”