The Mongol Empire emerged from the unification of Mongol and Turkic tribes of historical Mongolia under the leadership of Genghis Khan. Genghis Khan was proclaimed ruler of all Mongols in 1206. The empire grew rapidly under his rule and then under the rule of his descendants, who sent invasions in every direction. The vast transcontinental empire which connected the east with the west with an enforced Pax Mongolica allowed trade, technologies, commodities and ideologies to be disseminated and exchanged across Eurasia. The empire began to split as a result of wars over succession, as the grandchildren of Genghis Khan disputed whether the royal line should follow from Genghis's son and initial heir Ögedei, or one of his other sons such as Tolui, Chagatai, or Jochi.
The Toluids prevailed after a bloody purge of Ögedeid and Chagataid factions, but disputes continued even among the descendants of Tolui. After Möngke Khan died, rival kurultai councils would simultaneously elect different successors, the brothers Ariq Böke and Kublai, who then not only had to defy each other, but also deal with challenges from descendants of other of Genghis's sons.