Uzbekistan is a landlocked country in Central Asia. It is itself surrounded by five landlocked countries: Kazakhstan to the north; Kyrgyzstan to the northeast; Tajikistan to the southeast; Afghanistan to the south, Turkmenistan to the south-west. Its capital and largest city is Tashkent. Uzbekistan is part of the Turkic languages world, as well as a member of the Organization of Turkic States. While the Uzbek language is the majority spoken language in Uzbekistan, Russian is widely used as an inter-ethnic tongue and in government. Islam is the majority religion in Uzbekistan, most Uzbeks being non-denominational Muslims. In ancient times it largely overlapped with the region known as Sogdia, and also with Bactria. The first people recorded in Central Asia were Scythians who came from the northern grasslands of what is now Uzbekistan, sometime in the first millennium BC; when these nomads settled in the region they built an extensive irrigation system along the rivers. At this time, cities such as Bukhoro (Bukhara) and Samarqand (Samarkand) emerged as centres of government and high culture. By the fifth century BC, the Bactrian, Soghdian, and Tokharian states dominated the region. As China began to develop its silk trade with the West, Persian cities took advantage of this commerce by becoming centres of trade. Using an extensive network of cities and rural settlements the Sogdian intermediaries became the wealthiest of these Iranian merchants. As a result of this trade on what became known as the Silk Route, Bukhara, Samarkand and Khiva eventually became extremely wealthy cities, and at times Transoxiana (Mawarannahr) was one of the most influential and powerful Persian provinces of antiquity. A remote part of the Persian Empire, the area was briefly conquered by Alexander the Great, and was known as Sogdia at this time. It, or parts of it, then passed through the Seleucid Empire, Greco-Bactrian Kingdom, Kushan Empire, Hephthalite Empire, and Sasanian Empire. As Turkic peoples arrived in the area, largely replacing Iranic peoples, the Sogdian city-states formed part of the First Turkic Khaganate and Western Turkic Khaganate. Long before Islamic invasion, the region was ruled by Hindu kings for several centuries. Among all the dynasties, Kushan dynasty was the most remarkable and influential one. This period is well known the for expansion of science, art and culture from both Hinduism and Buddhism while both religions flourished in harmony. The region was at its peak glory during the period. The