Regarding massacre that occurred in Baghdad in 656H, Ibn Katheer states:
“When the Tartars descended on the city of Baghdad, they killed whomever they met of men, women and children, young and old. Many people tried to hide in wells, rubbish dumps and sewers, where they stayed for several days. Some people locked themselves in inns and guesthouses, but the Tartars broke into every such house, and chased the people they found there to the roofs where they killed them.
Gutters and alleys were overflowing with blood, and so were mosques and other places of worship. The only survivors were the Jews an the Christians in the city and those who sought refuge with them, and those who were given shelter in the house of Ibn Al-‘Alqamee, the Shee’ah minister. A group of businessmen were also spared and given safety after they had paid large sums of money for the purpose. Baghdad, which used to be the most friendly and peaceful of cities, was totally in ruin, inhabited only by a small portion of its original population, and even these were living in fear, hunger and humiliation.
Reports on the number of Muslims killed in Baghdad in this battle vary, with some estimating the dead to be 800,000, while other reports suggest the dead numbered 1,000,000, and still others putting the estimate at 2,000,000 people. We can only sy what Muslims are recommended to say at the time of a calamity, “To God we belong and to Him do we return… All power belongs to God, the Most High, the Almighty.”
The Tartars entered Baghdad towards the end of the month of Muharram, and continued the killing of its population for 40 days. The Caliph, Al-Mu’tasim Billaah was killed on Wednesday 14 Safar and his grave was erased. On the day of his death he was 46 years of age and 4 months. His reign lasted for 15 years, 8 months and a few days. His eldest son, Ahmad Aboo Al-‘Abbaas, was killed at the same time at the age of 25, while his middle son, ‘Abd Al-Rahmaan, who was 23, was killed a short while later. His youngest son, Mubaarak, and his 3 sisters, Faatimah, Khadeejah and Maryam, were taken prisoner.
The most prominent scholar in Baghdad, Shaykh Yoosuf Ibn Shaykh Aboo Al-Faraj Ibn Al-Jawzee, who was hostile to the Minister was killed together with his 3 sons, ‘Abdullaah, ‘Abd Al-Rahmaan and Abd Al-Kareem. All the nobility in the city were killed one by one. Prominent among these were Mujahid Al-Deen Aybak, and Shihaab Al-Deen Sulaymaan Shaah and many others. Anyone who belonged to the ‘Abbaas ruling family might be called out, and he would have to go with his women and children to the Al-Khallaal graveyard, where he would be slaughtered like a sheep. The Tartars might choose some of his daughters or other women in his household to keep as prisoners. The most prominent and eldest scholar in Baghdad, ‘Alee Ibn Al-Nayyaar, who had educated the Caliph when he was young, was also killed as well as most Imaams and scholars in the city. Mosques were abandoned and no congregational or Friday prayer was held in and mosque for several months in Baghdad.
After 40 days, when the massacre was over, Baghdad was in total ruin, with only the odd person walking about. Dead bodies were placed in heaps in the streets. Rain had changed their colour and their bodies had begun to rot. The smell in the city was most awful and there were outbreaks of several diseases which moved far and wide, reaching as far as Syria. People were then facing scarcity of necessary commodities, an unabating massacre, as well as epidemics. Those were indeed hard times.
When safety was announced for the survivors, those who were hiding in holes and graveyards came out. Thy looked so pale as though they were brought back from the dead. They were practically unrecognisable, to the extent that a father might not recognise his son, and brothers might not recognise each other. They were vulnerable to any disease and many of them soon died.”
[Al-Bidaayah Wan-Nihaayah, by Ibn Katheer, 13/199-203]