 in the first millennium bc, iranian nomads established irrigation systems along the rivers of central asia and built towns at bukhoro and samarqand. these places became extremely wealthy points of transit on what became known as the silk road between china and europe. in the seventh century ad, the soghdian iranians, who profited most visibly from this trade, saw their province of transoxiana (mawarannahr) overwhelmed by arabs, who spread islam throughout the region. under the arab abbasid caliphate, the eighth and ninth centuries were a golden age of learning and culture in transoxiana. as turks began entering the region from the north, they established new states, many of which were persianate in nature. after a succession of states dominated the region, in the twelfth century, transoxiana was united in a single state with iran and the region of khwarezm, south of the aral sea. in the early thirteenth century, that state was invaded by mongols, led by genghis khan. under his successors, iranian-speaking communities were displaced from some parts of central asia. under timur (tamerlane), transoxiana began its last cultural flowering, centered in samarqand. after timur the state began to split, and by 1510 uzbek tribes had conquered all of central asia."country profile: uzbekistan". library of congress federal research division (february 2007). this article incorporates text from this source, which is in the public domain. in the sixteenth century, the uzbeks established two strong rival khanates, bukhoro and khorazm. in this period, the silk road cities began to decline as ocean trade flourished. the khanates were isolated by wars with iran and weakened by attacks from northern nomads. between 1729 and 1741 all the khanates were made into vassals by nader shah of persia. in the early nineteenth century, three uzbek khanatesâbukhoro, khiva, and quqon (kokand)âhad a brief period of recovery. however, in the mid-nineteenth century russia, attracted to the region's commercial potential and especially to its cotton, began the full military conquest of central asia. by 1876 russia had incorporated all three khanates (hence all of present-day uzbekistan) into its empire, granting the khanates limited autonomy. in the second half of the nineteenth century, the russian population of uzbekistan grew and some industrialization occurred. at the beginning of the twentieth century, the jadidist movement of educated central asians, centered in present-day uzbekistan, began to advocate overthrowing russian rule. in 1916 violent opposition broke out in uzbekistan and elsewhere, in response to the conscription of central asians into 
History_of_Uzbekistan