In the Nineveh Plains, only a third of the Christian population that was driven by ISIS from their homes nearly four years ago has returned. A traumatized community is struggling to overcome the daunting reality of rebuilding an area left in a post-apocalyptic state. An area that is still insecure.

Related: Timeline of ISIS in Iraq
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Years ago, Iraq was home to one of the Middle East's most robust Christian communities. They numbered 1.4 million at the beginning of the 21st century. Today fewer than 250,000 Christians remain in the country--a near 80 percent drop. Like the Yezidis, a distinct religious minority in Iraq, the Christians have suffered massive atrocities at the hands of ISIS. Both the Trump and Obama administrations officially recognized that ISIS bore responsibility for genocide against these populations. In late July 2014, ISIS commanded the Christians to "leave or be killed." There could be no mistake: ISIS aimed to erase the Christians from its caliphate in northern Iraq. It struck a Christian community that was already extremely fragile, having faced severe persecution throughout the previous decade. ISIS' TOLL ISIS terrorists waged a bloody blitz through Iraq's Nineveh province, including its capital of Mosul, where Christian homes were stamped with the red Arabic letter "n" for "Nazarene," and throughout the Christian towns of the Nineveh Plains. Their assault on the Plains included crucifying, beheading, raping, kidnapping, torturing, and enslaving people. ISIS drove out every member of the region's 2,000-year-old Christian community.

Monasteries and churches were burned and destroyed--45 churches in Mosul alone. In January 2016, satellite imagery showed the complete obliteration of Mosul's massive, stone-walled monastery of St. Elijah, which dates back to the 6th century. The photos confirm reports that the monastery had been pulverized into gray dust by ISIS fanatics, evidently using a determined application of sledgehammers, bulldozers, and explosives.

Related: Church Bombings in Iraq Since 2004

ISIS' international propaganda magazine Dabiq, threatened: "We will conquer your Rome, break your crosses, and enslave your women." The cover photo showed St. Peter's Basilica in Vatican City with a black flag replacing the cross atop its dome. The terrorist organization claims that it offered an option to Nineveh's Christians to live peacefully under its control, a so-called "jizya" or tax option. This proved to be false--a publicity stunt to appear more caliph-like, according to former State Department counter-terrorism adviser Ambassador Alberto Fernandez. By the time ISIS consolidated its power over Nineveh in August 2014, there were no functioning churches, priests, pastors, or intact Christian communities remaining. The ancient Christian presence had been all but eradicated.

Rev. Emanuel Adelkello is a Syriac Catholic priest who directly dealt with ISIS over the fate of the Nineveh Christians that July. He related to me that the Christian leaders of Nineveh refused ISIS' demands to assemble at a Mosul civic center, purportedly to hear the groups' jizya demand. They decided it was a trap and that they would "likely be killed if they showed up." The priest added, "There was specific concern that the intention was to keep women there so that they could be taken freely by the ISIS fighters." When the Christians failed to follow ISIS orders to assemble, the militants told them to "leave or be killed." Everyone who could fled in a panic, after being stripped of their valuables. Syriac Catholic Patriarch Ignatius Joseph III Younan estimates that ISIS killed more than 500 Christians. It showed no mercy. Typically, a male was taken hostage in exchange for their families to leave. These men were never seen again. An Iraqi Catholic priest told me that in early 2016, he spoke with an Iraqi Christian woman who, displaced in Kurdistan, had witnessed jihadists crucifying her husband to the front door of their home before she fled. Mosul's Chaldean Catholic Archbishop Amel Nona wrote an open letter stating that a "huge number of Christians" from Mosul and the Nineveh Plains were killed. He gave an example of four children from a Qaraqosh family--ages four, six, eight, and 15--who were all killed. SEXUAL SLAVERY ISIS' sexual enslavement has been mostly associated with Yezidis, yet scores of Christians were also enslaved. The group published a price list of enslaved Christian and Yezidi females on sale at slave markets, with captives aged one to nine being the most expensive. A Nineveh family from Qaraqosh had their three-year-old daughter, Christina, snatched by ISIS militants. As reported in a New York Times magazine cover story, they learned she was detained in a holding pen with other women and girls and later sold at a Mosul slave market. Thankfully, little Christina was rescued during the liberation of Mosul. A disturbing story of a Christian mother who escaped ISIS enslavement is recounted in a June 2016 report of Minority Rights Group International. As a captive, she was brutally tortured and then taken to a sex slave detention center under the direction of an ISIS "sheikh" who performed eight "marriages" in one night between her and ISIS fighters, in accordance with their strict rules. Rita Ayyoub, a 30-year-old Christian woman, told journalists that she was taken to a slave market in Mosul and sold, along with three Christian children, to ISIS "emirs." A local Sunni man bought her and a 14-year-old Yezidi girl. "He raped the both of us over and over again," she says. She was sold twice more, including to a jihadi with a violent Moroccan wife. Ayyoub relates her ordeal in that family: "I was beaten and tortured by [the jihadi's wife] every day. She would not give up until I was bleeding, from my head, for example. They made me read the Quran and threatened to kill me if I did not convert to Islam." In November 2017, Ayyoub was rescued by Syrian Democratic Forces. ISIS also forced a father to watch his twelve-year-old daughter and her mother be raped by ISIS militants, causing him to commit suicide. Iraqi lawyers documented 68 Christians who were still in ISIS captivity as of August 2017. FORCED CONVERSIONS There are multiple reports of forced conversion. World magazine editor Mindy Belz interviewed Christians from Nineveh who fled ISIS. She wrote that in Qaraqosh, some one hundred Christians who were left behind ended up being held hostage in their homes. "One father described being tortured while his wife and two children were threatened after the family refused to deny their faith." A group of 14 Christian men reportedly converted when jihadists threatened to take a nine-year-old girl as a "bride." In another press account, a family of 12 Assyrian Christians, trapped in Bartella after ISIS arrived, was robbed and forcibly converted to Islam by a Mosul court. After the family members escaped, they said they saw one Assyrian who had not converted and was badly beaten--his hands were tied behind his back and he was driven off in a truck, they surmised, to be killed. The vast majority of Nineveh's Christians fled to Iraq's Kurdistan Region or to neighboring countries for safety. With cars and bus fare stolen by ISIS militants, many had to walk across miles of desert-like terrain in the peak of summer, with 120-degree-Fahrenheit temperatures and no water or food. How many sick or weak walkers died on this march remains unknown. CHRISTIAN PERSECUTION ISIS has not been the only persecutor of Christians. They have been relentlessly targeted by fanatics since a coordinated bombing of churches in Baghdad in 2004. Mosul's Bishop Rahho was assassinated in 2008. Two years later, a catastrophic suicide attack killed worshippers who filled the pews of a Catholic church in Baghdad. Such assaults were solely for religious reasons; the Christian minority lacks political power and has not taken up arms for any side in the region's numerous conflict. Ordinary Christians were targeted for "un-Islamic" dress, speech, behavior, worship, and businesses. Thousands were taken hostage and tortured or killed. By 2008, Christian kidnappings in Iraq became so common, Belz reports, that "ransom notes simply demanded daftar, slang which everyone knew meant $10,000." Christians have become vulnerable to kidnappings for ransom payments because of their ties to Western churches with deep pockets. But even when ransoms are paid, sometimes hostages are still killed. On July 10, 2015, the Vatican press Fides reported that, after families paid ransoms of up to $50,000, Christian hostages in Baghdad were killed instead of freed. Relatives have also been murdered when paying ransoms for loved ones. Iraqi Chaldean priest Douglas Bazi told me that he was held hostage for nine days in Baghdad, deprived of food and water for four days, and severely beaten with a hammer, which broke his back, skull and facial bones. In keeping with the times, his attackers acted with impunity. Today Christians and Yezidis are at an historic crossroads. What remains after ISIS are weakened, demoralized, remnant communities. Either Iraq's non-Muslim minorities receive help to leave their displacement shelters in Kurdistan and to rebuild their shattered towns or, in despair, they must emigrate. In that case, we will all see the extinction of their ancient communities, along with Iraq's religious pluralism.

Adapted from a chapter in The Persecution and Genocide of Christians in the Middle East. Nina Shea is the director of Hudson Institute's Center for Religious Freedom.