Iraqi Christian families, of those who fled from Mosul, Iraq and other nearby towns, gather at a building of a social club in Ainkawa, a suburb of Irbil with a majority Christian population, Iraq, Thursday, June 26, 2014 (Photo: AP)
Iraqi Christians are again under threat, with tens of thousands that fled after jihadists seized several northern towns Thursday just the latest wave to seek shelter elsewhere in the country and abroad.
Gunmen from the Sunni Muslim Islamic State (IS) seized Qaraqosh, Iraq's largest Christian town, and several others near Mosul following the withdrawal of Kurdish peshmerga fighters, inhabitants said.
Chaldean Catholic Patriarch Louis Sako called the occupation part of a "humanitarian disaster" that has displaced 100,000 Christians and seen churches occupied, their crosses removed and manuscripts burned.
In mid-July, thousands of Christians in Mosul fled after IS gave them an ultimatum to convert to Islam, pay jizya (protection money) or leave on pain of death.
The exodus raised concern in Western capital, and governments began to accept the fleeing Christians as refugees.
Before the US-led invasion of Iraq in 2003, the country had an estimated Christian population of more than one million, including more than 600,000 in Baghdad, 60,000 in Mosul and concentrations in the oil cities of Kirkuk and Basra.
The latest estimates put the overall number at around 400,000 with more than half living in the northern Nineveh province, of which Mosul is the capital.
Patriarch Sako says there were around 35,000 in Mosul before the IS launched an offensive, though other sources give lower figures, and almost all have since fled.
Christian tradition attributes the evangelisation of what is now Iraq to the apostles Thomas and Thaddeus, and their disciples Mari and Aggai.
Today, the majority of Iraqi Christians are Chaldean Catholics, members of a self-governing church in communion with Rome.
They initially followed Nestorianism, which taught that Christ's human and divine essences are separate and that there are two persons, the man Jesus Christ and the divine Logos, which dwelt in the man.
In the 16th century they renounced this belief, considered a heresy in the wider church, but conserved their rites that include a liturgy in Aramaic, the language of Jesus.
Iraq also has communities of Roman Catholics, as well as Syrian and Armenian Catholics.
Among non-Catholic faiths, the majority are Assyrians, who still adhere to the Nestorian doctrine, along with Syrian Orthodox, and Armenian Orthodox.
There are also Anglican and Protestant groups.
Former Iraqi dictator Saddam Hussein did not consider Christians a threat, and his last foreign minister, Tariq Aziz, is Chaldean.
But the invasion exacerbated divisions among many of Iraq's religious sects.
Identified with the Western Crusaders of the early Middle Ages, Iraqi Christians were targeted by sectarian violence.
In the past decade, around 60 churches have been attacked and 1,000 Christians killed.
In October 2010, 44 parishioners and two priests perished in an attack claimed by Al-Qaeda on Our Lady of Salvation Church, a Syrian Catholic mission in Baghdad.