dissemination and exchange of trade, technologies, commodities and ideologies across Eurasia. The Mongol invasion halted China's economic development for over 150 years, decisively changing the balance of power in the Eastern Hemisphere. The empire began to split due to wars over succession, as the grandchildren of Genghis Khan disputed whether the royal line should follow from his son and initial heir Ögedei or from 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 among the descendants of Tolui. After Möngke Khan died (1259), rival kurultai councils simultaneously elected different successors, the brothers Ariq Böke and Kublai Khan, who fought each other in the Toluid Civil War (1260–1264) and also dealt with challenges from the descendants of other sons of Genghis. Kublai successfully took power, but civil war ensued as he sought unsuccessfully to regain control of the Chagatayid and Ögedeid families. By the time of Kublai's death in 1294 the Mongol Empire had fractured into four separate khanates or empires, each pursuing its own separate interests and objectives: the Golden Horde khanate in the northwest, the Chagatai Khanate in Central Asia, the Ilkhanate in the southwest, and the Yuan dynasty in the east, based in modern-day Beijing. In 1304, the three western khanates briefly accepted the nominal suzerainty of the Yuan dynasty, but in 1368 the Han Chinese Ming dynasty took over the Mongol capital. The Genghisid rulers of the Yuan retreated to the Mongolian homeland and continued to rule there as the Northern Yuan dynasty. The Ming dynasty, the largest army in the world, with almost a million soldiers. It was therefore able to conduct military campaigns in Manchuria, Inner Mongolia, Yunnan, and Vietnam. Naval voyages were also sent, with the Ming treasure voyages reaching Africa. These also intervened militarily in Java, Sumatra, and Sri Lanka. The Ilkhanate disintegrated in the period 1335–1353. The Golden Horde had broken into competing khanates by the end of the 15th century and was defeated and thrown out of Russia in 1480 by the Grand Duchy of Moscow while the Chagatai Khanate lasted in one form or another until 1687. Middle East and Europe The Byzantine–Sasanian Wars of 572–591 and 602–628 produced the cumulative effects of a century of almost continuous conflict, leaving both empires crippled. When Kavadh II died only months after coming to the