Genghis Khan (/ˈɡɛŋɡɪs ˈkɑːn/ or /ˈdʒɛŋɡɪs ˈkɑːn/,Mongol: [tʃiŋɡɪs xaːŋ] ( listen); 1162? – August 1227), born Temujin, was the founder and Great Khan (emperor) of the Mongol Empire, which became the largest contiguous empire in history after his death.

He came to power by uniting many of the nomadic tribes of northeast Asia. After founding the Mongol Empire and being proclaimed "Genghis Khan", he started the Mongol invasions that resulted in the conquest of most of Eurasia. These included raids or invasions of the Kara-Khitan Khanate, Caucasus, Khwarezmid Empire, Western Xia and Jin dynasties. These campaigns were often accompanied by wholesale massacres of the civilian populations – especially in Khwarezmia. By the end of his life, the Mongol Empire occupied a substantial portion of Central Asia and China.

Before Genghis Khan died, he assigned Ögedei Khan as his successor and split his empire into khanates among his sons and grandsons. He died in 1227 after defeating the Western Xia. He was buried in an unmarked grave somewhere in Mongolia at an unknown location. His descendants went on to stretch the Mongol Empire across most of Eurasia by conquering or creating vassal states out of all of modern-day China, Korea, the Caucasus, Central Asian countries, and substantial portions of modern Eastern Europe, Russia and the Middle East. Many of these invasions resulted in the large-scale slaughter of local populations, which have given Genghis Khan and his empire a fearsome reputation in local histories.

Hulagu Khan, also known as Hülegü, Hulegu (Mongolian: Hülegü Khaan, "Warrior"; Mongolian Cyrillic: Хүлэг хаан; Turkish: Hülâgü Han; Chagatai/Urdu: ہلاکو Hulaku; Persian/Arabic: هولاكو خان‎; Chinese: 旭烈兀; c. 1217 – 8 February 1265), was a Mongol ruler who conquered much of Southwest Asia. Son of Tolui and the Kerait princess Sorghaghtani Beki, he was a grandson of Genghis Khan, and the brother of Arik Boke, Möngke Khan and Kublai Khan. Hulagu's army greatly expanded the southwestern portion of the Mongol Empire, founding the Ilkhanate of Persia, a precursor to the eventual Safavid dynasty, and then the modern state of Iran. Under Hulagu's leadership, the Mongols destroyed the greatest center of Islamic power, Baghdad, and also weakened Damascus, causing a shift of Islamic influence to the Mamluks in Cairo. During Hulagu's reign historians began writing in Persian instead of Arabic^{[citation needed]}.

Hulagu was born to Tolui, one of Genghis Khan's sons, and Sorghaghtani Beki, an influential Kerait princess. Sorghaghtani successfully navigated Mongol politics, arranging for all of her sons to become Mongol leaders. She was a Nestorian Christian, and Hulagu was friendly to Christianity. Hulagu's favorite wife, Dokuz Khatun, was also a Christian, as was his closest friend and general, Kitbuqa. It is recorded however that he was a Buddhist as he neared his death, against the will of Dokuz Khatun.