The brutal targeting of Christians and other minorities by ISIS has its roots in the history of the Caliphate. Christians in the Middle East are in minority and no real threat to ISIS. Even if ISIS established their Caliphate, Christians or other minorities won’t be able to stop them or even oppose them. One of ISIS’s main strategy is to inflame sectarian violence, however, until jihad is declared in all Islamic lands. In countries like Egypt or Iraq and other Islamic countries minorities have been living for centuries and even long before Islam appeared on the scene.
ISIS model of the Caliphate is partly inspired by the Abbasids. Baghdadi has been observed by some to have expressed fondness for the Abbasids Caliphate. The use of the colour black is their identification with the Abbasids who were the first to use black banners. The Abbasids have left an impressive legacy for ISIS leaders to aspire to as they endeavour to reestablish their Caliphate in Baghdad (or somewhere in the Middle East) where the Abbasids ruled. Baghdad is also the place the ISIS leader, Abu Bakr al-Baghdadi, had studied and earned his doctorate in Islamic law. He must have learned about the golden age of Islam during the Abbasids Caliphate while living and studying in Baghdad and also what brought their terrible downfall.
Baghdadi understanding of history and what contributed to the Abbasids rise and destruction is again a fanatical interpretation of the past. He does not make any distinction between those who are the enemy of Islam and those who are the enemy of the Caliphate. He is simultaneously the self-appointed caliph and the prophet of Islam.
What brought about the Abbasids downfall was tragic for the Muslim world. If religious minorities were not tolerated by the Abbasids, the Caliphate would have survived. If it was not for their collaboration with the Mongols, Halague could have never been able to sack Baghdad. However, minorities had lived under different Islamic caliphates, be it in Egypt, Spain or Syria or elsewhere and were even allowed to contribute to the state in a different capacity but under the Abbasids, they were treated discriminatory and when the opportunity presented itself to conspire with the enemies against the Abbasids they didn’t hesitate.
Baghdadi has failed to admit that the Abbasids collaborated with Chengiz Khan who slaughtered their fellow Muslim brothers and sisters. It has even been suggested that the Abbasids had petitioned Chengiz Khan to attack the kingdom of Khwarazm (Iran). The circumstantial evidence is pretty strong for that theory. The Abbasids did not declare war on Chengiz Khan and sided with him and did not want to upset him perhaps why they were largely left intact during his campaigns. By 1241 the Abbasids began sending an annual tribute to the court of the khagan. Envoys from the caliph were present at the coronation of Güyük Khan in 1246 and Möngke Khan in 1251.
When Chengiz Khan’s grandson, Halagu Khan was commissioned to expand the Mongol empire and establish the Illkhnate he had no mandate from Möngke Khan to destroy the Caliphate let alone kill the Caliph. The Abbasids had played their cards very carefully and skilfully to reach that level of immunity within the Mongol empire. Behind the scenes, they were slowly converting the Mongols of the Golden Horde to Islam and had been ingratiating themselves with the Mongols since Chengiz Khan military campaigns began. They wanted the Mongols to recognise them as their spiritual head and it was only a matter of time before the Abbasids were going to ride on the back of yet another military superpower and reign supreme. When Baghdad learned that Halagu was coming for them their efforts in diplomacy and evangelising all of a sudden came to nothing and undoubtedly they wondered what had wrong. No negotiations seemed to be working to convince Halagu not to attack them either. However, after 12 days of warfare, the Abbasids surrendered. Halague’s mandate to make the Abbasids submit unconditionally had succeeded and he should have halted there but he was hellbent on destroying Baghdad even going against what was sanctioned by the great Khan Möngke. Berke, another grandson of Chengiz Khan who was by then a Muslim and the head of the Golden Horde who had expressed the greatest admiration for the Abbasids never forgave his brother Halagu for killing the Caliph but Halagu didn’t care and later even went to war with Berke.
Perhaps fate or God had something to do with the annihilation of the Abbasids if you believe in any of those two. Or perhaps it was Tusi who was aware of the treatment of Shiites by the Abbasids encouraged Halague to not negotiate with the Abbasids. Tusi and Halagu met in Alamut for the first time and quickly became friends. But it is more likely that it was Halagu’s wife, Doguz Khatun who was a Christian and accompanied her husband on his war campaigns that convinced Halagu to sack Baghdad and free the Christians from the Abbasids oppressive rules. Even Halagu himself was educated by a Nestorian Christian although he was not a Christian himself. Halagu’s army also consisted of the king of Armenia and his troops. A Frankish contingent from Antioch and Georgian forces. As well as Chinese and Persians. This was no ordinary campaign to force the Abbasids to merely submit. The Abbasids had shown in more ways than one that they were willing to work with the Mongols and had the loftiest visions of collaboration with them.
After the capture of Baghdad, Halague’s army was given strict orders to spare the Christians and the Shiites as they slaughtered all the other Muslims. Christians were told to remain in their churches and Shiites holy sites were protected by Mongol guards. The killing continued for days, it was genocidal. 500 years of Abbasids rule had built up deep resentments and hatred for them from all the non-Sunni Muslims living under theri rule.
In the aftermath, the royal palace was offered to the Nestorian Catholicos, Mar Makikhas by Halague who also ordered a cathedral to be built for him. Tusi’s wish for establishing the grandest observatory in Maragheh was also granted and he went on holding the world’s first intercontinental conference in astronomy. Many minorities came out of hiding no longer fearing a backlash from the ruling religious elite.
The Sunni world may still hark back with sentimentality to their golden era, wondering what would have happened if the Abbasids had survived. However, Baghdadi is determined to continue where the Abbasids left off. The sacking of Baghdad by the Mongols assisted by the Christians and the Shiites would never happen again because there won’t be any minorities living in Baghdad's version of a caliphate. For him, Abbasids were too lenient with the religious minorities and they paid the price. Baghdadi's merciless attacks on the Christians and Shiites and other minorities will only get worse in the Muslim countries.
Christians in the Middle East, however, are also stabbed in the back by the largest Christian country in the world, the U.S. As the Saudis prepare the ground work by pouring money in educating people in their version of Islam (Wahhabism) in Africa and other places, ISIS’s work becomes much easier in recruiting people who already have been brainwashed. Trump’s Administration stamp of approval on the Saudis only gives them more freedom to spread their ideology and to ISIS greater supply of future volunteers and suicide bombers.
Shiites on other hand are betrayed by the largest Shiite country in the world, Iran. Although the Islamic Republic of Iran has managed to protect their own population against attacks by ISIS they have made the Shiites population outside of Iran the greatest target. Shiites in Pakistan, Iraq, Afghanistan and Yemen are constantly under attack and no one is able to protect them. Islamic Republic of Iran geopolitical ambitions is spilling far more Shiites blood than their Sunni rivals. But the ayatollahs are not too phased about their Shiite brothers and sisters being bombed to pieces by ISIS or the Saudis for they are considered ‘martyrs.’ As long as they serve the ‘Shiite’ cause they have not died in vain.