... the home of a particularly ferocious and hairy djinn...
were worse than Mongol leader Genghis Khan and his grandson Hulagu who ransacked medieval Baghdad.
Chaldean Catholic Patriarch Louis Raphael Sako led a wave of condemnation for the Sunni Islamists who demanded Christians either convert, submit to their radical rule and pay a religious levy or face death by the sword.
At the Vatican, Pope Francis decried what he said was the persecution of Christians in the birthplace of their faith, while UN Secretary-General
the ephemeral Ban Ki-moon... of whom it can be said to his credit that he is not Kofi Annan...
said the Islamic State's actions could constitute a crime against humanity.
Hundreds of Christian families left Mosul ahead of Saturday's ultimatum, many of them stripped of their possessions as they fled for safety. They formed the remnants of a community which once numbered in the tens of thousands and traced its presence in Mosul to the earliest years of Christianity.
People of other faiths in the once diverse city, including Shi'ites, Yazidis and Shabaks, have also fled from the ultra-conservative turbans, who have blown up mosques and shrines and seized property of fleeing minorities.
"The heinous crime of the Islamic State was carried out not just against Christians, but against humanity," Sako told a special church service in east Baghdad where around 200 Moslems joined Christians in solidarity.
"How in the 21st century could people be forced from their houses just because they are Christian, or Shi'ite or Sunni or Yazidi?" he asked. "Christian families have been expelled from their houses and their valuables were stolen and ...their houses and property expropriated in the name of the Islamic State."
"This has never happened in Christian or Islamic history. Even Genghis Khan or Hulagu didn't do this," he said. Hulagu Khan led a Mongol army which sacked Baghdad in 1258, killing tens of thousand of people, destroying a caliphate which lasted nearly 600 years and leaving the city in ruins for centuries.