According to Mongol custom the oldest son is assigned lands farthest away from the paternal homeland. Since the eldest son, Juji, died six months before his death, Genghis gave Batu, eldest son of Juji, the westernmost conquest, which included Russia, called the khanate of the Golden Horde.
His second son, Chagatai Khan, received most of Central Asia. His third son, Ogotai Khan, received western China and parts of Central Asia and was nominated (subject to confirmation by the Mongol council, or kuriltai) khaghan, or khan of khans.
Tului was given the homeland, Mongolia (Mongol custom gave the youngest the paternal homeland) plus northern China and the bulk of the main Mongol military forces of over 100,000 men. His control of this force would greatly benefit the fortune of his sons as they competed for control of the inheritance of Genghis Khan.
In 1203 after defeating his former ally the Kerait confederation (another nomad group), Genghis took its leader Ong Khan’s two nieces as war booty. He kept one as a minor wife for himself and wed the other, Sorghaghtani Beki, to Tului.
She and Tului had four sons, Mongke Khan, Kubilai Khan, Hulagu Khan, and Arik Boke. Since Tului was away campaigning much of the time and died young of alcoholism, his wife was influential in raising her sons.
She is credited with raising them not only to be hunters and warriors as Mongol tradition dictated, but also to read Mongol in the newly created Uighur script, to be religiously tolerant (she was a Nestorian Christian because of her Keriat heritage), and to attend to administration.
|Tului and his wife|
After Tului died Ogotai Khaghan attempted to marry Sorghaghtani Beki or have his son marry her (under Mongol custom), thus uniting the two branches of the family. She was able to avoid marrying them, with the plea that she had to raise her sons.
She also obtained an appanage, or fief, in northern China in presentday southwestern Hebei (Hopei) province, which she supervised conscientiously. Her second son, Kubilai, also received an appanage, which he first entrusted to alien managers who abused the population. Later under Sorghaghtani Beki’s influence, he took a personal interest in it and improved its administration.
Ogotai died in 1241. His powerful widow became regent and maneuvered the Mongol leaders to elect her son Guyuk as the third khaghan in 1246. Guyuk died in 1248. In a succession struggle that followed Sorghaghtani Beki, with the support of Batu Khan of the Golden Horde, won election for her oldest son, Mongke, in 1251.
Mongke raised Tului posthumously to the position of khaghan and buried him next to Genghis Khan; he also ordered the official worship of Genghis Khan and the veneration of his father, Tului Khan. His younger brother, Kubilai Khan, followed Mongke as khaghan.