The Silk Road: origins, merchants, and what actually moved along it

For most of the first millennium CE, the eastern half of the Silk Road was run by Sogdian merchants — Iranian-speaking traders from the oasis cities of Samarkand, Panjikent, and Bukhara^[2]. They spoke Sogdian (now extinct; the closest living descendant is Yaghnobi), wrote it in a script derived from Aramaic, and set up trading colonies from Xi'an in Tang China to Constantinople.

The Sogdian Ancient Letters — a bundle of letters found in a Han-dynasty watchtower in western China, written in ~313 CE — are among the oldest surviving paper documents anywhere in the world. They are addressed by Sogdian merchants to their families in Samarkand.

Silk was one item among many. In roughly descending order of value the westbound Silk Road carried: silk (naturally), paper (a Samarkand innovation after 751 CE — see below), Chinese ceramics, gunpowder, rhubarb, printing techniques, and mathematics; the eastbound carried gold, silver, wool, glass, wine, horses, and Christian, Manichaean, and Nestorian religious texts.

Ideas moved more freely than goods. Buddhism entered China from India via Sogdian and Kushan intermediaries. Nestorian Christianity reached Tang China via Sogdian and Syriac missionaries — a Nestorian stele from 781 CE stands in Xi'an. Later, Islam moved east through the same channels.

One of the Silk Road's most consequential single events was the Battle of Talas in 751 CE, at which an Abbasid army defeated Tang China at a river near modern Taraz (Kazakhstan). Chinese prisoners of war included papermakers; the Abbasids brought them to Samarkand, where they set up the Islamic world's first paper mill^[3]. Within fifty years, Samarkand paper was being shipped to Baghdad; within two centuries, to Cairo, Fez, and Al-Andalus. The Konigil paper mill outside Samarkand still uses the exact 8th-century method today.

Vasco da Gama's Portuguese maritime route to India in 1498 made overland trade slower and more expensive than sea trade for most goods. Timurid dynastic collapse and the emergence of the Uzbek Shaybanid state in the 16th century further disrupted the trade. The great trans-Asian caravan trade never fully recovered — though the local caravan network survived into the 19th century.