The first people known to inhabit the Central Asian region of modern-day Uzbekistan were Iranian nomads who arrived from the northern grasslands of what is now Kazakhstan sometime in the first millennium BC. These nomads, who spoke Iranian dialects, settled in Central Asia and began to build an extensive irrigation system along the rivers of the region. At this time, cities such as Bukhoro (Bukhara), Samarqand (Samarkand) and Chash (Tashkent) began to appear as centers of emerging government and high culture. By the 5th century BC, the Bactrian, Soghdian, and Tokharian states dominated and ruled over the region.As China began to develop its silk trade with the West, Iranian cities took advantage of this commerce by becoming centres of trade. Using an extensive network of cities and rural settlements in the province of Mouwaurannahr (a name given the region after the Arab conquest) in Uzbekistan, and further east in what is today China's Xinjiang Uygur Autonomous Region, the Soghdian intermediaries became the wealthiest of these Iranian merchants.
Because of this trade on what became known as the Silk Route, Bukhoro and Samarqand eventually became extremely wealthy cities, and at the times Mawarannahr was the only large and one of the most influential and powerful Persian provinces of antiquity in human history.Macedonian ruler Alexander the Great conquered Sogdiana and Bactria in 327 BC, marrying Roxana, daughter of a local Bactrian chieftain. A conquest was supposedly of little help to Alexander as popular resistance was fierce, causing Alexander's army to be bogged down in the region that became the northern part of Hellenistic Greco-Bactrian Kingdom. For many centuries the region of Uzbekistan was ruled by Persian empires, including the Parthian and Sassanid Empires, as well as by other empires, formed by the Hephthalite and Gokturk peoples.In the 8th century Mouverannakhr (territory between the Amudarya and Syrdarya rivers) was conquered by Arabs (Ali ibn Sattor), which inherited the region with the Early Renaissance. Many notable scientists have lived and contributed during the Islamic Golden Age.
Among the achievements of the scholars during this period were the development of trigonometry into its modern form (simplifying its practical application to calculate the phases of the moon), advances in optics, in astronomy, as well as in poetry, philosophy, art, calligraphy and many other, which have set the foundations for a Muslim Renaissance.In the 9th – 10th centuries, Mouverannakhr was included into the Samanid State. Later, Mouverannakhr saw the incursion of the Turkic-ruled Karakhanids, as well as the Seljuks (Sultan Sanjar) and Kara-Khitans. The Mongol conquest under Genghis Khan during the 13th century would bring about a change to the region. The conquest and characteristic expansion of the Mongols led to the displacement of some of the Iranian-speaking people of the region, their culture and heritage being superseded by that of the Mongolian-Turkic peoples who came thereafter.Following the death of Genghis Khan in 1227, his empire was divided among his four sons and his family members. Despite the potential for serious fragmentation, Mongol law of the Mongol Empire maintained orderly succession for several more generations, and control of most of Mouverannakhr stayed in the hands of direct descendants of Chagatai Khan, the second son of Genghis Khan. Orderly succession, prosperity, and internal peace prevailed in the Chaghatai lands, and the Mongol Empire as a whole remained strong and united kingdom. In the early 14th century, however, as the empire began to break up into its constituent parts, the Chaghatai territory also was disrupted as the princes of various tribal groups competed for influence.
One tribal chieftain, Timur (Tamerlane), emerged from these struggles in the 1380s as the dominant force in Mouverannakhr. Although he was not a descendant of Chinggis, Timur became the de facto ruler of Mouverannakhr and proceeded to conquer all of western Central Asia, Iran, Asia Minor, and the southern steppe region north of the Aral Sea. He also invaded Russia, Turkey, Iraq, and placed under his command Iran and India, before dying during an invasion of China in 1405.Timur initiated the last flowering of Mouverannakhr by gathering in his capital, Samarqand, numerous artisans and scholars from the vast lands he had conquered. By supporting such people, Timur imbued his empire with a very rich Perso-Islamic culture. During Amir Timur's reign and the reigns of his immediate descendants, a wide range of religious and palatial construction masterpieces were undertaken in Samarqand and other population centres. Timur also initiated exchange of medical thoughts and patronized physicians, scientists and artists from the neighboring countries like India; his grandson Ulughbek was one of the world's first great astronomers. It was during the Timurid dynasty that Turkic, in the form of the Chaghatai dialect, became a literary language in its own right in Mouverannakhr, although the Timurids were Persianate in nature. The Timurid state quickly broke into two halves after the death of Timur. The chronic internal fighting of the Timurids attracted the attention of the Uzbek nomadic tribes living to the north of the Aral Sea. In 1501 the Uzbek forces began a wholesale invasion of Mouverannakhr. The slave trade in the Khanate of Bukhara became prominent and was firmly established. Estimates from 1821 suggest that between 25,000 and 60,000 Persian slaves were working only in Bukhara at the time.In the 19th century, the Russian Empire began to expand and spread into Central Asia.
The "Great Game" period is generally regarded as running from approximately 1813 to the Anglo-Russian Convention of 1907. Following the Bolshevik Revolution of 1917, a second, less intensive phase followed. At the start of the 19th century, there were some 3,200 kilometres (2,000 mi) separating British India and the outlying regions of Tsarist Russia. Much of the land in between was unmapped. By the beginning of 1920, Central Asia was firmly in the hands of Russia and, despite some early resistance to the Bolsheviks, Uzbekistan and the rest of the Central Asia became a part of the Soviet Union. On October 27, 1924 the Uzbek Soviet Socialist Republic was created. From 1941 to 1945, during World War II, 1,433,230 people from Uzbekistan fought in the Red Army against Nazi Germany. (A number also fought on the German side.) 263,005 Uzbek soldiers died in the battlefields of the Eastern Front, 132,670 went missing in action. On August 31, 1991, Uzbekistan declared independence, proclaiming September 1 as the National Independence Day.