...Samarkand begin to appear at this time as centers of government and culture.

The Bactrian, Sogdian, and Tocharian states dominate the region of modern Uzbekistan by the fifth century BCE.

As China begins to develop its silk trade with the West, Iranian cities take advantage of this commerce by becoming centers of trade.

Using an extensive network of cities and settlements in the province of Mawarannahr (a name given the region after the Arab conquest) in Uzbekistan and farther east in what is today China's Xinjiang Uygur Autonomous Region, the Sogdian intermediaries become the wealthiest of these Iranian merchants.

Because of this trade on what becomes known as the Silk Route, Bukhara and Samarkand will eventually become extremely wealthy cities, and the Mawarannahr region is at times one of the most influential and powerful Persian provinces of antiquity.

The Royal Road of the Persian Empire by the time of Herodotus (circa 475 BCE) runs some two thousand eight hundred and fifty-seven kilometers (one thousand seven hundred and seventy-five miles) from the city of Susa on the Karun (two hundred and fifty kilometers (one hundred and fifty-five miles) east of the Tigris) to the port of Smyrna (modern İzmir in Turkey) on the Aegean Sea.

Maintained and protected by the Achaemenid Empire (circa 500–330 BCE), it features postal stations and relays at regular intervals.

The wealth of the Mawarannahr region is a constant magnet for invasions from the northern steppes and from China.

Numerous intraregional wars are fought between Sogdian states and the other states in Mawarannahr, and the Persians and the Chinese are in perpetual conflict over the region.

Alexander the Great conquers the region in 328 BCE, bringing it briefly under the control of his Macedonian Empire.

In the same centuries, however, the region also is an important center of intellectual life and religion.

Alexander now advances with his army from the Sogdian capital of Maracanda (modern Samarkand) …

Spitamenes has meanwhile raised all Sogdia in revolt behind him, bringing in the Massagetai, a people of the Saka confederacy, and besieging the Macedonian garrison in Maracanda.

Alexander sends an army under the command of Pharnuches of Lycia that is promptly annihilated with a loss of more than two thousand infantry and three hundred cavalry.

Understanding now the danger represented by his enemy, Alexander moves personally to relieve Maracanda, only to learn that Spitamenes has left Sogdiana.

It takes Alexander until the autumn of 328 to crush the most determined opponent he encounters in his campaigns.

An incident that occurs at Maracanda widens the breach between Alexander and many of his Macedonians.

He murders Cleitus, one of his most trusted commanders, with his own hands in a drunken quarrel; but his excessive display of remorse leads the army to pass a decree convicting Cleitus posthumously of treason.

The event marks a step in Alexander's progress toward Eastern absolutism, and this growing attitude finds its outward expression in his use of Persian royal dress.

Spitamenes is badly defeated in December by Alexander's general Coenus at the Battle of Gaba, at which point Spitamenes' allies, feeling the situation desperate, kill their leader and send his head as a gift to Alexander.

Zoroastrianism is the dominant religion in Central Asia until the first centuries after Christ, but Buddhism, Manichaeism, and Christianity also attract large numbers of followers.

…Xuanzang crosses the desert further west to Samarkand.

In Samarkand, which is under Persian influence, the party comes across some abandoned Buddhist temples and Xuanzang impresses the local king with his preaching.

Setting out again to the south, …

The conquest of Central Asia by Islamic Arabs brings to the region a new religion and culture that continue to be dominant.

The Arabs first invade Mawarannahr in the middle of the seventh century through sporadic raids during their conquest of Persia.

Available sources on the Arab conquest suggest that the Sogdians and other Iranian peoples of Central Asia were unable to defend their land against the Arabs because of internal divisions and the lack of strong indigenous leadership.

The Arabs, on the other hand, are led by a brilliant general, Qutayba ibn Muslim, and they also are highly motivated by the desire to spread their new faith (the official beginning of which was in CE 622).

Because of these factors, the population of Mawarannahr is easily conquered.

The new religion brought by the Arabs spreads gradually in the region.

The native cultures, which in some respects already were being displaced by Persian influences before the Arabs arrived, will be displaced further in the ensuing centuries.

The destiny of Central Asia as an Islamic region is nevertheless firmly established by the Arab victory over the Chinese armies in 750 in a battle at the Talas River.

Central Asia retains much of its Iranian character under Arab rule, remaining an important center of culture and trade for centuries after the Arab conquest.

The language of government, literature, and commerce will be Arabic, however, until the tenth century.

Mawarannahr continuesd to be an important political player in regional affairs, as it had been under various Persian dynasties.

In fact, the Abbasid Caliphate, which will rule the Arab world for five centuries, beginning in 750, is established thanks in great part to assistance from Central Asian supporters in their struggle against the then-ruling Umayyad Caliphate.

…Samarkand, …