statues of the Buddha. 22 Tibetan Empire Main article: Tibetan Empire Map of the Tibetan Empire at its greatest extent between the 780s and the 790s CE The history of a unified Tibet begins with the rule of Songtsen Gampo (604650 CE who united parts of the Yarlung River Valley. The zone has a planned area.46 km2 (2.11 sq mi) and is divided into two zones. 98 99 Desideri, who reached Lhasa in 1716, encountered Armenian and Russian merchants. It is employed throughout the Tibetan plateau and Bhutan and is also spoken in parts of Nepal and northern India, such as Sikkim. Journey Across Tibet: A Young Woman's 1,900-mile (3,060 km) Trek Across the Rooftop of the World. 1,"d from Wu, Zaoqi Chuanjiaoshi jin Zang Huodongshi,.