Who finally conquered the Abbasid Dynasty in 1258?

, under the leadership of Hulagu Khan (one of Kublai Khan’s brothers)
With the death of the Islamic prophet Mohammed (PBUH – which means Peace Be Upon Him – and is used to show respect for the prophet by Muslims) in 632 AD, there was turmoil in the Islamic faith over who should be the Caliph (which means not just a religious leader but also a political leader of the people as well). The majority Sunni faction saw their pick, Abu Bakr, assume the role of Caliph.
After the death of Abu Bakr, the Caliphate passed down through three other men, with Ali (the original choice by the Shia faction) becoming Caliph in 656, making Ali the 4th Caliph in Sunni reckoning and the 1st Caliph in Shia reckoning. The period of these leaders is known as the Rashidun Caliphate.
The deaths of the men who followed Abu Bakr were all assassinations and highlighted two big problems:

The expansion of the Islamic Caliphate was tremendous in both area and time it took to happen, expanding from a small piece of Saudi Arabia during Mohammed’s lifetime, to an empire that extended from Persia, through the Middle East, and extended all the way across northern Africa. With this very fast expansion came assassins from conquered lands.

The divided allegiance of Muslims into the Sunni and Shia camps. For instance, there is still debate as to whether the assassination of Uthman, Ali’s predecessor, was aided by Ali (he was either unable or unwilling to capture the rebels who assassinated Uthman, which made a lot of people suspicious and may have played a part in Ali’s own assassination).

Ali left the Caliphate to his son, who quickly turned it over to the leader of the biggest and strongest army in the land, a Sunni named Mu’awiyah, who founded the Umayyad Caliphate (661-750). Once again, the Caliphate expanded greatly and quickly. And once again, internal divisions led to its downfall as the Shia unified and defeated the Umayyad’s in a series of battles (one big complaint people had to the Umayyads was that they had no relation to Mohammed, unlike all the Caliphs before this one). But the Caliphate, instead of passing to a Shia, went instead to a rival house, Abbasids (750-1258, 1261-1517).
(The diagram above shows the Caliphate, from 622 to 750
In dark brown, the expansion under Muhammad, 622–632
In dark tan, the expansion during the Rashidun Caliphs, 632–661
In lighter tan, the expansion during the Umayyad Caliphate, 661–750)
It was during the Abbasid Caliphate that Islamic culture hit its high mark, with scientific, religious, and cultural flourishing. They moved the capital to Baghdad and it became a centre for knowledge, culture, and trade. But it was also during this Caliphate that the expansion of the Caliphate toppled – different areas began to revolt, self-govern, and claim autonomy from the Caliphate. By 920 AD, the Abbasid’s had control only over the territory that is now modern day Iraq. And it all came crashing down with the Mongol invasion in 1258.
What was left of the Abbasid’s made their way to Egypt and declared themselves Caliph from their new centre in Cairo – but it was only a religious Caliphate – they held no true political power. And this ended in 1517 when the Ottomans invaded and made Egypt part of the Ottoman Empire.
https://en.wikipedia.org/wiki/Caliphatehttps://en.wikipedia.org/wiki/Abbasid_Caliphatehttps://en.wikipedia.org/wiki/Umarhttps://en.wikipedia.org/wiki/Abu_Bakr