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.

Kublai Khan ( /ˈkuːblə ˈkɑːn/; Mongolian: Хубилай хаан, Xubilaĭ xaan; Middle Mongolian: Qubilai Qaγan, "King Qubilai"; September 23, 1215 – February 18, 1294), born Kublai (Mongolian: Хубилай, Xubilaĭ; Middle Mongolian: Qubilai; Chinese: 忽必烈; pinyin: Hūbìliè; also spelled Khubilai) and also known by the temple name Shizu (Chinese: 元世祖; pinyin: Yuán Shìzǔ; Wade–Giles: Yüan Shih-tsu), was the fifth Great Khan of the Mongol Empire from 1260 to 1294 and the founder of the Yuan Dynasty in China.

As he was the second son of Tolui and Sorghaghtani Beki, and a grandson of Genghis Khan, he claimed the title of Khagan of the Ikh Mongol Uls (Mongol Empire) in 1260 after the death of his older brother Möngke in the previous year, though his younger brother Ariq Böke was also given this title in the Mongolian capital, Karakorum. Kublai won the battle against Ariq Böke in 1264 and the succession war marked the beginning of disunity in the empire. Kublai's real power was limited to China and Mongolia (which was the Yuan Dynasty, or the Mongol Dynasty) after the victory over Ariq Böke, though his influence still remained in the Ilkhanate and, to a far lesser degree, in the Golden Horde in the western parts of the Mongol Empire. If one counts the Mongol Empire at that time as a whole, his realm reached from the Pacific to the Urals, from Siberia to modern day Afghanistan – one fifth of the world's inhabited land area.