Hulagu (1217 – 1265) was a grandson of Genghis Khan and younger brother of the Grand Khans Mongke and Kublai, who expanded the Mongol domain into Western Asia with a savagery that remains in the region’s memory to this day. He destroyed Baghdad and extinguished the Abbasid Caliphate, conquered Syria, menaced Egypt and the surviving Crusader states, and while destroying medieval Persian culture, founded the Ilkhanate in Persia, a precursor of modern Iran.
In 1251, Hulagu was recognized by his brother Mongke as ruler of the Ilkhanate in Persia and tasked to extend Mongol power into the Islamic world. As a preliminary, Hulagu attacked and exterminated the Assassins cult, a militant Islamic sect that had terrorized the Middle East for generations. He then turned to the Abbasid Caliphate, and when the Caliph refused to submit, Hulagu invaded and besieged him in Baghdad, captured the city in 1258 and destroyed it along with all its treasures, such as the Grand Library of Baghdad, and massacred between 200,000 to a million inhabitants. To avoid a Mongol taboo against spilling royal blood, the captured Caliph was executed by being rolled into a carpet, which was then trampled by Mongols riding over it. That ended the Abbasids and the Islamic institution of the Caliphate.
Hulagu then conquered Syria, bringing to an end the Ayubbid dynasty founded by Saladin. He then set his eyes on Egypt, but on the eve of the invasion, he received word that his brother Mongke had died. As a potential successor, Hulagu returned to Mongolia, and in his absence, the Mongols he left behind under a trusted subordinate were wiped out by the Egyptian Mamluks at the Battle of Ain Jalut in 1260 – the first major defeat of a Mongol army, and one that broke the spell of Mongol invincibility.
Hulagu was not selected to succeed his brother as Great Khan, so he returned west to avenge the defeat at Ain Jalut, but ended up warring with a cousin, Batu Khan’s brother Berke, who had succeeded to the leadership of the Golden Horde, converted to Islam, and was enraged by Hulagu’s rampage in the Muslim world. The war with Berke was Hulagu’s main focus for the remainder of his life, until his death in 1265.