During the Tubo Regime, a great number of irrigation projects developed along the Yarlong River and the Yarlung Tsangpo River, and with the increase of yaks and horses here there was dramatic development in agriculture. However, continued conflict led to endless famine and eventually the collapse of the Tubo regime. In 1253, Möngke Khan, the emperor of Yuan Dynasty, invaded Tibet and united the squabbling tribes into an administrative region, controlled by the central government of Yuan Dynasty in Beijing. However, the dominant tribe in the Yarlung valley during this period was the Pazhu Dynasty and in 1322, Qiangqujianqun became the leader of the Pazhu and replenished agricultural activity in the region, funding irrigation works, cultivating lands, reconstructing roads, restoring houses and developing husbandry. Qiangqujiangqun founded the Naidong Dynasty which would last for 262 years, introduced the system of feudal serfdom and implemented a new government system with divisions known as Zong, established 13 of them in Nêdong (the capital), Gonggar and so forth.